freedreno/ir3: Add workaround for VS samgq

freedreno/ir3: Add workaround for VS samgq

This instruction needs a workaround when used from vertex shaders.

Fixes:

  dEQP-GLES3.functional.shaders.texture_functions.texturegradoffset.sampler2dshadow_vertex
  dEQP-GLES3.functional.shaders.texture_functions.texturegradoffset.sampler3d_fixed_vertex
  dEQP-GLES3.functional.shaders.texture_functions.texturegradoffset.sampler3d_float_vertex
  dEQP-GLES3.functional.shaders.texture_functions.textureprojgradoffset.sampler2dshadow_vertex
  dEQP-GLES3.functional.shaders.texture_functions.textureprojgradoffset.sampler3d_fixed_vertex
  dEQP-GLES3.functional.shaders.texture_functions.textureprojgradoffset.sampler3d_float_vertex
  dEQP-GLES3.functional.shaders.texture_functions.textureprojgrad.sampler2dshadow_vertex

Signed-off-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>