File PATCH_POLICY of Package grub2-rhel-7.4-multiarch-branchpoint

Make sure the patches you add contain tags similar to patches in the kernel
RPM. This means, it should contain From, Subject, Patch-mainline tags and also
a description of the problem, i.e. what the patch is for.

Also, if it is not a SUSE/openSUSE-specific patch (unlikely is), post the patch to
upstream too.