9p: Fix missing commas in mount options

9p: Fix missing commas in mount options

commit 61b272c3aa170b3e461b8df636407b29f35f98eb upstream.

Since commit c4fac9100456 ("9p: Implement show_options"), the mount
options of 9p filesystems are printed out with some missing commas
between the individual options:

p9-scratch on /mnt/scratch type 9p (rw,dirsync,loose,access=clienttrans=virtio)

Add them back.

Fixes: c4fac9100456 ("9p: Implement show_options")
Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>