kbuild: Use a single clean rule for kernel and external modules

The list of patterns for the external modules case was constantly
lagging behind.

Signed-off-by: Michal Marek <mmarek@suse.cz>

Makefile

@@ -1186,15 +1186,7 @@ PHONY += $(clean-dirs) clean archclean
 $(clean-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
 
-clean: archclean $(clean-dirs)
-	$(call cmd,rmdirs)
-	$(call cmd,rmfiles)
-	@find . $(RCS_FIND_IGNORE) \
-		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
-		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-		-o -name '*.symtypes' -o -name 'modules.order' \
-		-o -name modules.builtin -o -name '.tmp_*.o.*' \
-		-o -name '*.gcno' \) -type f -print | xargs rm -f
+clean: archclean
 
 # mrproper - Delete all generated files, including .config
 #
@@ -1392,16 +1384,7 @@ $(clean-dirs):
 	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
 
 clean:	rm-dirs := $(MODVERDIR)
-clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers \
-                   $(KBUILD_EXTMOD)/modules.order \
-                   $(KBUILD_EXTMOD)/modules.builtin
-clean: $(clean-dirs)
-	$(call cmd,rmdirs)
-	$(call cmd,rmfiles)
-	@find $(KBUILD_EXTMOD) $(RCS_FIND_IGNORE) \
-		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
-		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-		-o -name '*.gcno' \) -type f -print | xargs rm -f
+clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
 
 help:
 	@echo  '  Building external modules.'
@@ -1418,6 +1401,16 @@ prepare: ;
 scripts: ;
 endif # KBUILD_EXTMOD
 
+clean: $(clean-dirs)
+	$(call cmd,rmdirs)
+	$(call cmd,rmfiles)
+	@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
+		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
+		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
+		-o -name '*.symtypes' -o -name 'modules.order' \
+		-o -name modules.builtin -o -name '.tmp_*.o.*' \
+		-o -name '*.gcno' \) -type f -print | xargs rm -f
+
 # Generate tags for editors
 # ---------------------------------------------------------------------------
 quiet_cmd_tags = GEN     $@