drm/amd/display: Solve mst monitors blank out problem after resume

[Why]
In dm resume, we firstly restore dc state and do the mst resume for topology
probing thereafter. If we change dpcd DP_MSTM_CTRL value after LT in mst reume,
it will cause light up problem on the hub.

[How]
Revert commit 202dc359 ("drm/amd/display: Defer handling mst up request in resume").
And adjust the reason to trigger dc_link_detect by DETECT_REASON_RESUMEFROMS3S4.

Cc: stable@vger.kernel.org
Fixes: 202dc359 ("drm/amd/display: Defer handling mst up request in resume")
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>