Fix warnings from clang-16

Running clang-16 on mbedtls reports warnings of type "-Wstrict-prototypes".
This patch fixes these warnings by adding void to functions with no
arguments. The generate_test_code.py is modified to insert void into test
functions with no arguments in *.function files.

Signed-off-by: Gowtham Suresh Kumar <gowtham.sureshkumar@arm.com>
diff --git a/programs/fuzz/common.c b/programs/fuzz/common.c
index 56b9a13..96a24f7 100644
--- a/programs/fuzz/common.c
+++ b/programs/fuzz/common.c
@@ -13,7 +13,7 @@
 }
 #endif
 
-void dummy_init()
+void dummy_init(void)
 {
 #if defined(MBEDTLS_PLATFORM_TIME_ALT)
     mbedtls_platform_set_time(dummy_constant_time);