drm/amd/display: Fix rotated cursor offset calculation

Underflow is observed when cursor is still enabled when the cursor
rectangle is outside the bounds of it's surface viewport.

Update parameters used to determine when cursor should be disabled.

Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: David Galiffi <David.Galiffi@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
3 files changed