drm/amd/display: Fix Cursor Offset in Scaled Scenarios

[WHY]
Cursor position code had improper offsets in scaled modes.

[HOW]
Adjust cursor scaling to account for cursor offsets properly.

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Sung Lee <sunglee@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>