x86: Add missing .note.GNU-stack to assembly source
Add .note.GNU-stack assembly source to avoid linker warning:
ld: warning: /tmp/ccPZSZ7Z.o: missing .note.GNU-stack section implies executable stack
ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
FAIL: gcc.target/i386/iamcu/test_3_element_struct_and_unions.c compilation, -O0