kbuild: Do not delete empty files in make distclean

Commit 3d64b449 introduced an empty file under
arch/arm/mach-zynq/board_dt.c. While this was not intended and the file
was removed from the tree by a later commit, we really should only match
junk files by known name patterns and not their size.
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

Makefile

@@ -1198,7 +1198,7 @@ distclean: mrproper
 	@find $(srctree) $(RCS_FIND_IGNORE) \
 		\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
 		-o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
-		-o -name '.*.rej' -o -size 0 \
+		-o -name '.*.rej' \
 		-o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
 		-type f -print | xargs rm -f