9p: Remove redundant inode uid/gid assignment

Remove a redundant update of inode's i_uid and i_gid
after v9fs_get_inode() since the latter already sets up
a new inode and sets the proper uid and gid values.

Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>