drm/amd/display: Fix system hang while resume with TBT monitor

[Why]
Connected with a Thunderbolt monitor and do the suspend and the system
may hang while resume.

The TBT monitor HPD will be triggered during the resume procedure
and call the drm_client_modeset_probe() while
struct drm_connector connector->dev->master is NULL.

It will mess up the pipe topology after resume.

[How]
Skip the TBT monitor HPD during the resume procedure because we
currently will probe the connectors after resume by default.

Reviewed-by: Wayne Lin <[e-mail]>
Signed-off-by: Tom Chung <[e-mail]>
Signed-off-by: Fangzhi Zuo <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

···
 		return;
 	}
 
+	/* Skip DMUB HPD IRQ in suspend/resume. We will probe them later. */
+	if (notify->type == DMUB_NOTIFICATION_HPD && adev->in_suspend) {
+		DRM_INFO("Skip DMUB HPD IRQ callback in suspend/resume\n");
+		return;
+	}
+
 	link_index = notify->link_index;
 	link = adev->dm.dc->links[link_index];
 	dev = adev->dm.ddev;