9p: missing chunk of "fs/9p: Don't update file type when updating file attributes"

commit b577d0cd2104fdfcf0ded3707540a12be8ddd8b0 upstream.

In commit 45089142 Aneesh had missed one (admittedly, very unlikely
to hit) case in v9fs_stat2inode_dotl().  However, the same considerations
apply there as well - we have no business whatsoever to change ->i_rdev
or the file type.

Cc: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>