media: v4l2-async: Fix error handling on steps after finding a match

media: v4l2-async: Fix error handling on steps after finding a match

Once an async connection is found to be matching with an fwnode, a
sub-device may be registered (in case it wasn't already), its bound
operation is called, ancillary links are created, the async connection
is added to the sub-device's list of connections and removed from the
global waiting connection list. Further on, the sub-device's possible own
notifier is searched for possible additional matches.

Fix these specific issues:

- If v4l2_async_match_notify() failed before the sub-notifier handling,
  the async connection was unbound and its entry removed from the
  sub-device's async connection list. The latter part was also done in
  v4l2_async_match_notify().

- The async connection's sd field was only set after creating ancillary
  links in v4l2_async_match_notify(). It was however dereferenced in
  v4l2_async_unbind_subdev_one(), which was called on error path of
  v4l2_async_match_notify() failure.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: "Yew, Chang Ching" <chang.ching.yew@intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>