SPRT: Rename the folder name to 'runtime'

The original name 'sprt' can be confusing if user did not read
SPRTL related document, hence rename it as 'runtime' to
indicate it is a secure partition runtime API set.

Signed-off-by: Ken Liu <Ken.Liu@arm.com>
Change-Id: I3ba7d5e80dd2ee32d52463bcdf012a2f5bf6017c
diff --git a/secure_fw/partitions/lib/runtime/rt_main.c b/secure_fw/partitions/lib/runtime/rt_main.c
new file mode 100644
index 0000000..e9ad7be
--- /dev/null
+++ b/secure_fw/partitions/lib/runtime/rt_main.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include "compiler_ext_defs.h"
+#include "runtime_defs.h"
+#include "sprt_partition_metadata_indicator.h"
+#include "rt_main.h"
+
+extern void common_sfn_thread(void);
+
+__used static uintptr_t runtime_init_c(void)
+{
+    struct runtime_metadata_t *p_rt_meta;
+
+    p_rt_meta = PART_METADATA();
+
+    if (p_rt_meta->n_sfn == 0) {
+        /* IPC Partition */
+        return p_rt_meta->entry;
+    } else {
+        /* SFN Partition */
+        return (uintptr_t)common_sfn_thread;
+    }
+}
+
+#if defined(__ICCARM__)
+#pragma required = runtime_init_c
+#endif
+
+__naked void sprt_main(void)
+{
+    __asm volatile(
+#if !defined(__ICCARM__)
+        ".syntax unified    \n"
+#endif
+        "bl runtime_init_c  \n"
+        "bx r0              \n"
+    );
+}