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 <wayne.lin@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>