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>

drivers/gpu/drm/i915/intel_display.c

@@ -2090,6 +2090,8 @@ static unsigned int intel_cursor_alignment(const struct drm_i915_private *dev_pr
 		return 16 * 1024;
 	else if (IS_I85X(dev_priv))
 		return 256;
+	else if (IS_I845G(dev_priv) || IS_I865G(dev_priv))
+		return 32;
 	else
 		return 4 * 1024;
 }