drm/radeon/dpm: fix display gap programming on SI
drm/radeon/dpm: fix display gap programming on SI

Need to set the DISP*_GAP fields as well as the
DISP*_GAP_MCHG fields.  Same as on previous asics.

Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs