<Make> Fix for using relative path instead of abs path

- make helper function was using realpath which cause creation
  of full path in the build dir which is not correct

mk/mk_helper.mk

@@ -42,6 +42,6 @@ define check_config_and_include
 ifeq ($(realpath $(1)),)
 $$(info < ! > Invalid $(2) ...)
 else
-include $(realpath $(1))
+include $(1)
 endif
 endef