0663c68c4d
Merge {CLEAN,MRPROPER,DISTCLEAN}_DIRS into {CLEAN,MRPROPER,DISTCLEAN}_FILES because the difference is just the -r option passed to the 'rm' command. Do likewise as commit 1634f2bfdb84 ("kbuild: remove clean-dirs syntax"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>