fs/9p: remove redundant pointer v9ses

Pointer v9ses is being assigned the value from the return of inlined
function v9fs_inode2v9ses (which just returns inode->i_sb->s_fs_info).
The pointer is not used after the assignment, so the variable is
redundant and can be removed.

Cleans up clang scan warnings such as:
fs/9p/vfs_inode_dotl.c:300:28: warning: variable 'v9ses' set but not
used [-Wunused-but-set-variable]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>