OMAPDSS: APPLY: print warning if wait_pending_extra_info_updates fails

wait_pending_extra_info_updates() currently does a hacky second check
for extra_info_update_ongoing() at the end of the function to show a
warning if extra_info update is still ongoing. The call to
extra_info_update_ongoing() should really be inside spinlock, but that's
a bit heavy just for verification.

Rather than that, check the return value of the
wait_for_completion_timeout() and print an error if it has timeouted or
returned an error.

Even better would be to return the error value and act on it in the
callers of wait_pending_extra_info_updates. However, it's not clear what
the callers should do in case of an error, as the error should only
happen if there's a bug in the driver or the HW. So we'll just print the
warning for now.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>