cm3: Only inline asm is allowed in naked functions

According to: https://gcc.gnu.org/onlinedocs/gcc-6.2.0/gcc/ARM-Function-Attributes.html

"Only basic asm statements can safely be included in naked functions (see Basic
Asm). While using extended asm or a mixture of basic asm and C code may appear
to work, they cannot be depended upon to work reliably and are not supported."

lib/cm3/vector.c

@@ -59,7 +59,7 @@ vector_table_t vector_table = {
 	}
 };
 
-void __attribute__ ((weak, naked)) reset_handler(void)
+void __attribute__ ((weak)) reset_handler(void)
 {
 	volatile unsigned *src, *dest;
 	funcp_t *fp;