drm/i915: Relax 845/865 CURBASE alignemnt requirement to 32 bytes

Supposedly 845/865 require only 32 byte alignment for CURBASE. Let's
relax the checks to allow that instead of demanding 4KiB alignment.
This will allow cursor panning in 8 pixel units.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327185546.2977-15-ville.syrjala@linux.intel.com


Reviewed-by: Imre Deak <imre.deak@intel.com>