i965/sf: Replace push/pop in brw_emit_anyprim_setup.

i965/sf: Replace push/pop in brw_emit_anyprim_setup.

Each of the subroutine emitters alter the predication state, but
otherwise don't change anything (or put it back when they do).
Resetting predication at the end makes these functions idempotent with
regard to the default instruction state - which is a nice property.

With that in place, push/pop is no longer necessary.

v2: Improve whitespace (requested by Matt).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>