Revert "Makefile: Do not quote value for CONFIG_CC_IMPLICIT_FALLTHROUGH"
This reverts commit cd8c917a56f20f48748dd43d9ae3caff51d5b987.
Commit 129ab0d2d9f3 ("kbuild: do not quote string values in
include/config/auto.conf") provided the final solution.
Now reverting the temporary workaround.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>