[Why]
1. No real HPD plug in/out but HPD happens,
 the driver notifies OS connection changed.
2. No display in target.

When HPD goes low to high,
the driver should regard as HPD and enter setmode flow.

[How]
In this case, even stream didn't change but still retrain.
Signed-off-by: NChiawen Huang <chiawen.huang@amd.com>
Signed-off-by: NCharlene Liu <charlene.liu@amd.com>
Reviewed-by: NTony Cheng <Tony.Cheng@amd.com>
Acked-by: NAnthony Koo <Anthony.Koo@amd.com>
Acked-by: NBhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>