[Why]
When determining synchronzied vblank we don't need to compare the stream
with itself

[How]
If comparing same stream, continue to next iteration
Signed-off-by: NAlvin Lee <alvin.lee2@amd.com>
Reviewed-by: NJun Lei <Jun.Lei@amd.com>
Acked-by: NQingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>