GEN9_PIPE_PLANE_FLIP_DONE() only works for planes 1-4. Extend
it handle planes 5-7 as well. Somewhat annoyingly the bits are
spread around into two distinct clumps.

Currently this doesn't achieve anything, but if we ever extend
async flip support to more than just the first plane then we'll
need this.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240605111832.21373-5-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>