i965/gen7: Call gen7_create_constant_surface instead of brw_[...].

i965/gen7: Call gen7_create_constant_surface instead of brw_[...].

Fixes 17 piglit tests:
- glsl-vs-arrays-3
- glsl-vs-texturematrix-2
- glsl-vs-uniform-array-2
- arl
- nv-arl
- nv-init-zero-addr
- vp-address-01
- vp-arl-constant-array
- vp-arl-constant-array-huge
- vp-arl-constant-array-huge-offset
- vp-arl-constant-array-huge-offset-neg
- vp-arl-constant-array-huge-relative-offset
- vp-arl-constant-array-huge-varying
- vp-arl-env-array
- vp-arl-local-array
- vp-arl-neg-array
- vp-arl-neg-array-2

Fixes 4 glean tests:
- glsl1-constant array of vec4 with variable indexing, vertex shader
- glsl1-constant array with variable indexing, vertex shader
- glsl1-constant array with variable indexing, vertex shader (2)
- vp1-ARL test

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>