i965/fs: Delay setup of uniform loads until after pre-regalloc scheduling.

i965/fs: Delay setup of uniform loads until after pre-regalloc scheduling.

This should fix the register allocation explosion on the GLES 3.0 test
on gen6.  It also gives us an instruction that will fit our CSE handling.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
NOTE: This is a candidate for the 9.1 branch.