kbuild: fix make clean after mismerge

Fix typo / thinko in commit bc081dd.

Signed-off-by: Michal Marek <[e-mail]>

Makefile

···
 		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.symtypes' -o -name 'modules.order' \
-		-o modules.order -o -name '.tmp_*.o.*' \
+		-o -name modules.builtin -o -name '.tmp_*.o.*' \
 		-o -name '*.gcno' \) -type f -print | xargs rm -f
 
 # mrproper - Delete all generated files, including .config