New review comment by brxken128 on void-packages repository

https://github.com/void-linux/void-packages/pull/41131#discussion_r1051448683

Comment:
> I think it's allowed to do something like `license="custom:linux-firmware" in such cases - maybe someone can correct/confirm me on that.

It seems to be allowed, [chromium-widevine does something similar.](https://github.com/void-linux/void-packages/blob/7dd7a5b371a82f5e6605c082d3dcf50cbaf8baee/srcpkgs/chromium-widevine/template)