drm/nouveau/disp/ga10[24]: initial support

UEFI/RM no longer use IED scripts from the VBIOS, though they appear to
have been updated for use by the x86 VBIOS code, so we should be able to
continue using them for the moment.

Unfortunately, we require some hacks to do so, as the BeforeLinkTraining
IED script became a pointer to an array of scripts instead, without a
revbump of the relevant tables.

There's also some changes to SOR clock divider fiddling, which are
hopefully correct enough that things work as they should.

AFAIK, GA100 shouldn't have display, so it hasn't been added.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>