kbuild: remove {CLEAN,MRPROPER,DISTCLEAN}_DIRS

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 1634f2bf ("kbuild: remove clean-dirs syntax").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Makefile

@@ -1397,14 +1397,14 @@ endif # CONFIG_MODULES
 # make distclean Remove editor backup files, patch leftover files and the like
 
 # Directories & files removed with 'make clean'
-CLEAN_DIRS  += include/ksym
-CLEAN_FILES += modules.builtin modules.builtin.modinfo modules.nsdeps
+CLEAN_FILES += include/ksym \
+	       modules.builtin modules.builtin.modinfo modules.nsdeps
 
 # Directories & files removed with 'make mrproper'
-MRPROPER_DIRS  += include/config include/generated          \
+MRPROPER_FILES += include/config include/generated          \
 		  arch/$(SRCARCH)/include/generated .tmp_objdiff \
-		  debian/ snap/ tar-install/
-MRPROPER_FILES += .config .config.old .version \
+		  debian snap tar-install \
+		  .config .config.old .version \
 		  Module.symvers \
 		  signing_key.pem signing_key.priv signing_key.x509	\
 		  x509.genkey extra_certificates signing_key.x509.keyid	\
@@ -1412,12 +1412,10 @@ MRPROPER_FILES += .config .config.old .version \
 		  *.spec
 
 # Directories & files removed with 'make distclean'
-DISTCLEAN_DIRS  +=
 DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
 
 # clean - Delete most, but leave enough to build external modules
 #
-clean: rm-dirs  := $(CLEAN_DIRS)
 clean: rm-files := $(CLEAN_FILES)
 
 PHONY += archclean vmlinuxclean
@@ -1430,7 +1428,6 @@ clean: archclean vmlinuxclean
 
 # mrproper - Delete all generated files, including .config
 #
-mrproper: rm-dirs  := $(wildcard $(MRPROPER_DIRS))
 mrproper: rm-files := $(wildcard $(MRPROPER_FILES))
 mrproper-dirs      := $(addprefix _mrproper_,scripts)
 
@@ -1439,18 +1436,15 @@ $(mrproper-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
 
 mrproper: clean $(mrproper-dirs)
-	$(call cmd,rmdirs)
 	$(call cmd,rmfiles)
 
 # distclean
 #
-distclean: rm-dirs  := $(wildcard $(DISTCLEAN_DIRS))
 distclean: rm-files := $(wildcard $(DISTCLEAN_FILES))
 
 PHONY += distclean
 
 distclean: mrproper
-	$(call cmd,rmdirs)
 	$(call cmd,rmfiles)
 	@find $(srctree) $(RCS_FIND_IGNORE) \
 		\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
@@ -1740,7 +1734,6 @@ $(clean-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
 
 clean: $(clean-dirs)
-	$(call cmd,rmdirs)
 	$(call cmd,rmfiles)
 	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
@@ -1835,11 +1828,8 @@ tools/%: FORCE
 	$(Q)mkdir -p $(objtree)/tools
 	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*
 
-quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN   $(wildcard $(rm-dirs)))
-      cmd_rmdirs = rm -rf $(rm-dirs)
-
 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
-      cmd_rmfiles = rm -f $(rm-files)
+      cmd_rmfiles = rm -rf $(rm-files)
 
 # Run depmod only if we have System.map and depmod is executable
 quiet_cmd_depmod = DEPMOD  $(KERNELRELEASE)

arch/um/Makefile

@@ -140,7 +140,7 @@ export CFLAGS_vmlinux := $(LINK-y) $(LINK_WRAPS) $(LD_FLAGS_CMDLINE)
 # When cleaning we don't include .config, so we don't include
 # TT or skas makefiles and don't clean skas_ptregs.h.
 CLEAN_FILES += linux x.i gmon.out
-MRPROPER_DIRS += arch/$(SUBARCH)/include/generated
+MRPROPER_FILES += arch/$(SUBARCH)/include/generated
 
 archclean:
 	@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \