Cppcheck: properly fail when finding errors

Makefile

@@ -329,7 +329,7 @@ line-count-x86:
 	cloc --force-lang-def cloc_lang_def.txt src/boot_x86_fsp.c src/boot_x86_fsp_payload.c src/boot_x86_fsp_start.S src/image.c src/keystore.c src/libwolfboot.c src/loader.c src/string.c src/update_disk.c src/x86/ahci.c src/x86/ata.c src/x86/common.c src/x86/gpt.c src/x86/hob.c src/pci.c src/x86/tgl_fsp.c hal/x86_fsp_tgl.c hal/x86_uart.c
 
 cppcheck:
-	cppcheck -f --suppress="ctunullpointer" --suppress="nullPointer" --suppress="objectIndex" --suppress="comparePointers" --std=c89 src/*.c hal/*.c hal/spi/*.c hal/uart/*.c
+	cppcheck -f --suppress="ctunullpointer" --suppress="nullPointer" --suppress="objectIndex" --suppress="comparePointers" --error-exitcode=89 --std=c89 src/*.c hal/*.c hal/spi/*.c hal/uart/*.c
 
 %.o:%.c
 	@echo "\t[CC-$(ARCH)] $@"