drm/msm: Fix setup of a6xx create_address_space.

We don't want it under CONFIG_DRM_MSM_GPU_STATE, we need it all the
time (like the other GPUs do).

Fixes: ccac7ce3 ("drm/msm: Refactor address space initialization")
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Rob Clark <robdclark@chromium.org>