9p: remove unused 'super_block' struct pointer

Get rid of the useless '*sb' variable.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

fs/9p/vfs_inode.c

@@ -779,7 +779,6 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 				      unsigned int flags)
 {
 	struct dentry *res;
-	struct super_block *sb;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *dfid, *fid;
 	struct inode *inode;
@@ -791,7 +790,6 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 	if (dentry->d_name.len > NAME_MAX)
 		return ERR_PTR(-ENAMETOOLONG);
 
-	sb = dir->i_sb;
 	v9ses = v9fs_inode2v9ses(dir);
 	/* We can walk d_parent because we hold the dir->i_mutex */
 	dfid = v9fs_fid_lookup(dentry->d_parent);