software: Makefile: Do not run cppcheck for kernel

Signed-off-by: Vaibhav Gupta <vaibhav.gupta@cern.ch>

software/Makefile

@@ -26,5 +26,8 @@ $(C_DIRS): include
 $(DIRS):
 	$(MAKE) -C $@ $(ENV_VAR) $(TARGET)
 
-flawfinder cppcheck:
+flawfinder:
 	for d in $(C_DIRS); do $(MAKE) -C $$d $@ || exit 1; done
+
+cppcheck:
+	$(MAKE) -C tools cppcheck