drm/amd/display: Eliminate several Maximus-specific code paths

This allows Maximus emulation to more closely mirror actual silicon
execution.

* Enable pool->base.display_clock creation on Maximus.
* Enable rest of dce110_apply_ctx_to_hw on Maximus.
* Remove apply_ctx_to_hw_fpga (no longer necessary with the full
  dce110_apply_ctx_to_hw enabled).
* Disable the dmcu->funcs->set_psr_wait_loop call in dce112_set_clock
  for Maximus (this was the only fix-up necessary after enabling
  dce110_apply_ctx_to_hw; everything else works unmodified on
  Maximus).

Signed-off-by: Ken Chalmers <ken.chalmers@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>