lint: always remove temporary files

In the error case, they survived.

Change-Id: I15167be12ff9ee03f1b3bb86b93f20cb5be02b10
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/6583
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
diff --git a/Makefile.inc b/Makefile.inc
index 42ed707..0a6b7bb 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -368,7 +368,7 @@
 		fi; \
 		echo ========; \
 	done; \
-	test $$FAILED -eq 0 || { echo "ERROR: $$FAILED test(s) failed." &&  exit 1; }; \
+	test $$FAILED -eq 0 || { echo "ERROR: $$FAILED test(s) failed."; rm -f $$LINTLOG && exit 1; }; \
 	rm -f $$LINTLOG
 
 gitconfig: