i965/fs: Set up gen7 UBO loads as sends from GRFs.

i965/fs: Set up gen7 UBO loads as sends from GRFs.

This gives the instruction scheduler a chance to schedule between the
loads, whereas before it was restricted due to the dependencies between
the MRFs for setting them up.

For one shader in gles3conform, it goes from getting stuck in register
allocation for as long as anybody's bothered to leave it running down
to 23 seconds, thanks to the LIFO scheduling.

Acked-by: Kenneth Graunke <kenneth@whitecape.org>