If this function fails to touch a dummy header due to missing parent
directory, then it creates it and touches the file again.
This was needed because CONFIG_FOO_BAR was previously tracked by
include/config/foo/bar.h. (include/config/foo/ may not exist here)
This is no longer the case since commit 0e0345b77a ("kbuild: redo
fake deps at include/config/*.h"); now all the fake headers are placed
right under include/config/, like include/config/FOO_BAR.
Do not try to create parent directory, include/config/, which already
exists.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
fee762d69a