drm/i915: Introduce plane->can_async_flip()

Move the "does this modifier support async flips?" check
to be handled by the platform specific plane code instead
of having a big mess in common code.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241009182207.22900-4-ville.syrjala@linux.intel.com


Reviewed-by: Jouni Högander <jouni.hogander@intel.com>