graphics/drm-current-kmod: Update after FreeBSD 1400037

While here update the comment to reflect the correct version shipped.
And remove the comment about amdgpu and EFI as I never had the problem
so it's not something general.

Sponsored by: Beckhoff Automation GmbH & Co. KG

(cherry picked from commit 7b66dded882913831735bfdcdaa376c9b4e5601e)