Pull 9p updates from Dominique Martinet:
 A bunch of small fixes:

   - three W=1 warning fixes: the NULL -> "" replacement isn't trivial
     but is serialized identically by the protocol layer and has been
     tested

   - one syzbot/KCSAN datarace annotation where we don't care about
     users messing with the fd they passed to mount -t 9p

   - removing a declaration without implementation

   - yet another race fix for trans_fd around connection close: the
     'err' field is also used in potentially racy calls and this isn't
     complete, but it's better than what we had

   - and finally a theorical memory leak fix on serialization failure"

* tag '9p-for-6.7-rc1' of https://github.com/martinetd/linux:
  9p/net: fix possible memory leak in p9_check_errors()
  9p/fs: add MODULE_DESCRIPTION
  9p/net: xen: fix false positive printf format overflow warning
  9p: v9fs_listxattr: fix %s null argument warning
  9p/trans_fd: Annotate data-racy writes to file::f_flags
  fs/9p: Remove unused function declaration v9fs_inode2stat()
  9p/trans_fd: avoid sending req to a cancelled conn