udf_process_sequence() allocates temporary array for processing
partition descriptors on volume which it fails to free. Free the array
when it is not needed anymore.

Fixes: 7b78fd02 ("udf: Fix handling of Partition Descriptors")
CC: stable@vger.kernel.org
Reported-by: syzbot+128f4dd6e796c98b3760@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>