kbuild: make distclean remove tag files in sub-directories

'make tags' and friends create tag files in the top directory, but
people may manually create tag files in sub-directories.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Makefile

@@ -1511,9 +1511,6 @@ MRPROPER_FILES += include/config include/generated          \
 		  signing_key.x509.signer vmlinux-gdb.py \
 		  *.spec
 
-# Directories & files removed with 'make distclean'
-DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
-
 # clean - Delete most, but leave enough to build external modules
 #
 clean: rm-files := $(CLEAN_FILES)
@@ -1540,16 +1537,14 @@ mrproper: clean $(mrproper-dirs)
 
 # distclean
 #
-distclean: rm-files := $(wildcard $(DISTCLEAN_FILES))
-
 PHONY += distclean
 
 distclean: mrproper
-	$(call cmd,rmfiles)
 	@find . $(RCS_FIND_IGNORE) \
 		\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
 		-o -name '*.bak' -o -name '#*#' -o -name '*%' \
-		-o -name 'core' \) \
+		-o -name 'core' -o -name tags -o -name TAGS -o -name 'cscope*' \
+		-o -name GPATH -o -name GRTAGS -o -name GSYMS -o -name GTAGS \) \
 		-type f -print | xargs rm -f