drm/i915: Move VT-d alignment into plane->min_alignment()

drm/i915: Move VT-d alignment into plane->min_alignment()

Currently we don't account for the VT-d alignment w/a in
plane->min_alignment() which means that panning inside a larger
framebuffer can still cause the plane SURF to be misaligned.
Fix the issue by moving the VT-d alignment w/a into
plane->min_alignment() itself (for the affected platforms).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250122151755.6928-2-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>