Extra DRM sources

[Robert Swindells <rjs%fdy2.co.uk@localhost>]

I would like to import the source to some extra DRM drivers from Linux,
would do lima, panfrost and vc4.

The layout that I'm using in my own tree is to put the GPL ones in a
sys/external/gpl2/drm2 tree that mirrors the existing bsd/drm2 tree.

The lima sources apart from lima_regs.h are dual licenced so will put
them under bsd/drm2.

All files will be from the same v5.6-rc3 branch of Linux as the current
drm sources.

Do I need to do a vendor import of this or just add the files?

Robert Swindells