drm/amd/display: Account for cursor prefetch BW in DML1 mode support

[Description]
We need to ensure to take into account cursor prefetch BW in
mode support or we may pass ModeQuery but fail an actual flip
which will cause a hang. Flip may fail because the cursor_pre_bw
is populated during mode programming (and mode programming is
never called prior to ModeQuery).

Reviewed-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Alvin Lee <alvin.lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>