drm/amd/display: reject both non-zero src_x and src_y only for DCN1x

[Why]
Video plane gets rejected for non-zero src_y and src_x on DCN2.x.

[How]
Limit the rejection till DCN1.x and verified MPO, by dragging video
playback beyond display's left (0, 0) co-ordinates.

Fixes: d89f6048 ("drm/amd/display: Reject non-zero src_y and src_x for video planes")
Signed-off-by: Shirish S <shirish.s@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>