toolchain: Add __noinline attribute

Add a new attribute to instruct the compiler to not inline a function.

Signed-off-by: Flavio Ceolin <flavio.ceolin@gmail.com>

include/zephyr/toolchain/gcc.h

@@ -225,6 +225,10 @@ do {                                                                    \
 #define __aligned(x)	__attribute__((__aligned__(x)))
 #endif
 
+#ifndef __noinline
+#define __noinline      __attribute__((noinline))
+#endif
+
 #define __may_alias     __attribute__((__may_alias__))
 
 #ifndef __printf_like