kbuild: also delete temporary directories

Reuse the standard naming schema for temporary files also for temporary
directories.

Such a directory will be used by the kheaders generation.

Signed-off-by: Thomas Weißschuh <[e-mail]>
Reviewed-by: Nicolas Schier <[e-mail]>
Tested-by: Nicolas Schier <[e-mail]>
Signed-off-by: Masahiro Yamada <[e-mail]>

Makefile

···
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
 		-o -name '*.symtypes' -o -name 'modules.order' \
-		-o -name '.tmp_*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
 		-o -name '*.gcno' \
-		-o -name '*.*.symversions' \) -type f -print | xargs rm -f
+		-o -name '*.*.symversions' \) -type f -print \
+		-o -name '.tmp_*' -print \
+		| xargs rm -rf
 
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