intel/vec4: Set brw_stage_prog_data::has_ubo_pull

intel/vec4: Set brw_stage_prog_data::has_ubo_pull

In 0e4a75f917, Ken added a flag brw_stage_prog_data which indicates
whether any UBO pulls ever occur.  Unfortunately, he neglected to set
the bit in the vec4 back-end.  This was fine at the time because the
optimization was intended for iris which does not support gen7 and using
the vec4 back-end on Gen8+ requires an environment variable.  We want to
use this in Vulkan which does support Gen7 so we want the information
from the vec4 back-end as well as scalar.

Fixes: 0e4a75f917 "intel/compiler: Record whether any pull constant..."
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>