refactor: remove `stdnoreturn.h` includes

The `noreturn` macro and `_Noreturn` keywords are deprecated in C23. The
reccommended way to indicate noreturn is now `[[noreturn]]`, which uses
the new C23 attribute syntax.

Change-Id: Ib923fce8bbe97597aa5ed27bb0962a107191022b
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
diff --git a/test/hftest/common.c b/test/hftest/common.c
index be4c44c..84ad7e4 100644
--- a/test/hftest/common.c
+++ b/test/hftest/common.c
@@ -104,7 +104,7 @@
 /**
  * Logs a failure message and shut down.
  */
-noreturn void abort(void)
+[[noreturn]] void abort(void)
 {
 	HFTEST_LOG("FAIL");
 	arch_power_off();
diff --git a/test/hftest/device_psci.c b/test/hftest/device_psci.c
index b27338f..d146026 100644
--- a/test/hftest/device_psci.c
+++ b/test/hftest/device_psci.c
@@ -10,7 +10,7 @@
 
 #include "test/hftest.h"
 
-noreturn void hftest_device_reboot(void)
+[[noreturn]] void hftest_device_reboot(void)
 {
 	arch_reboot();
 }
diff --git a/test/hftest/nwd_el0_service.c b/test/hftest/nwd_el0_service.c
index acf7aeb..c766ad7 100644
--- a/test/hftest/nwd_el0_service.c
+++ b/test/hftest/nwd_el0_service.c
@@ -17,7 +17,7 @@
 	hftest_service_set_up(ctx, fdt);
 }
 
-noreturn void kmain(const void *fdt_ptr)
+[[noreturn]] void kmain(const void *fdt_ptr)
 {
 	hftest_service_main(fdt_ptr);
 }
diff --git a/test/hftest/power_mgmt.c b/test/hftest/power_mgmt.c
index 787a7fe..edd250b 100644
--- a/test/hftest/power_mgmt.c
+++ b/test/hftest/power_mgmt.c
@@ -22,7 +22,7 @@
 	struct spinlock lock;
 };
 
-static noreturn void cpu_entry(uintptr_t arg)
+[[noreturn]] static void cpu_entry(uintptr_t arg)
 {
 	/*
 	 * The function prototype must match the entry function so we permit the
diff --git a/test/hftest/secondary_no_fdt.c b/test/hftest/secondary_no_fdt.c
index 445ba86..02869db 100644
--- a/test/hftest/secondary_no_fdt.c
+++ b/test/hftest/secondary_no_fdt.c
@@ -26,7 +26,7 @@
 	hftest_service_set_up(ctx, fdt);
 }
 
-noreturn void kmain(size_t mem_size)
+[[noreturn]] void kmain(size_t mem_size)
 {
 	/*
 	 * Initialize the stage-1 MMU and identity-map the entire address space.
diff --git a/test/hftest/sel0_secure_service.c b/test/hftest/sel0_secure_service.c
index c8cb995..cf6b928 100644
--- a/test/hftest/sel0_secure_service.c
+++ b/test/hftest/sel0_secure_service.c
@@ -34,7 +34,7 @@
 	hftest_service_set_up(ctx, fdt);
 }
 
-noreturn void kmain(struct ffa_boot_info_header* boot_info_blob)
+[[noreturn]] void kmain(struct ffa_boot_info_header* boot_info_blob)
 {
 	boot_info_header = boot_info_blob;
 
diff --git a/test/hftest/sel1_secure_service.c b/test/hftest/sel1_secure_service.c
index 452ab1f..127d3e1 100644
--- a/test/hftest/sel1_secure_service.c
+++ b/test/hftest/sel1_secure_service.c
@@ -48,7 +48,7 @@
 	hftest_service_set_up(ctx, fdt);
 }
 
-noreturn void kmain(struct ffa_boot_info_header* boot_info_blob)
+[[noreturn]] void kmain(struct ffa_boot_info_header* boot_info_blob)
 {
 	/*
 	 * Initialize the stage-1 MMU and identity-map the entire address space.
diff --git a/test/hftest/service.c b/test/hftest/service.c
index b4673fc..77c2252 100644
--- a/test/hftest/service.c
+++ b/test/hftest/service.c
@@ -22,7 +22,7 @@
 	hftest_service_set_up(ctx, fdt);
 }
 
-noreturn void kmain(const void *fdt_ptr)
+[[noreturn]] void kmain(const void *fdt_ptr)
 {
 	/*
 	 * Initialize the stage-1 MMU and identity-map the entire address space.
diff --git a/test/hftest/service_common.c b/test/hftest/service_common.c
index 78f6400..b48c8b6 100644
--- a/test/hftest/service_common.c
+++ b/test/hftest/service_common.c
@@ -59,7 +59,7 @@
 	*out = (uint32_t)num;
 }
 
-noreturn void abort(void)
+[[noreturn]] void abort(void)
 {
 	HFTEST_LOG("Service contained failures.");
 	/* Cause a fault, as a secondary/SP can't power down the machine. */
@@ -278,7 +278,7 @@
 	}
 }
 
-noreturn void hftest_service_main(const void *fdt_ptr)
+[[noreturn]] void hftest_service_main(const void *fdt_ptr)
 {
 	struct hftest_context *ctx;
 	struct memiter args;
diff --git a/test/hftest/standalone_main_secure.c b/test/hftest/standalone_main_secure.c
index b38a4cc..71c2ce0 100644
--- a/test/hftest/standalone_main_secure.c
+++ b/test/hftest/standalone_main_secure.c
@@ -24,7 +24,7 @@
 	return boot_info_header;
 }
 
-static noreturn void hftest_wait(void)
+[[noreturn]] static void hftest_wait(void)
 {
 	for (;;) {
 		interrupt_wait();