kbuild: fix up CFLAGS usage
Sam Ravnborg authored

Only in very rare cases is it needed to change CFLAGS
outside of arch/*/Makefile.
Fix up all wrong cases - in most cases
the use of EXTRA_CFLAGS is the only thing needed.
Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
9a39e273