kill simple_set_mnt()

not needed anymore, since all users (->get_sb() instances) are gone.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namespace.c

@@ -466,14 +466,6 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt)
 	br_write_unlock(vfsmount_lock);
 }
 
-void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
-{
-	mnt->mnt_sb = sb;
-	mnt->mnt_root = dget(sb->s_root);
-}
-
-EXPORT_SYMBOL(simple_set_mnt);
-
 void free_vfsmnt(struct vfsmount *mnt)
 {
 	kfree(mnt->mnt_devname);

include/linux/fs.h

@@ -1839,7 +1839,6 @@ extern struct dentry *mount_pseudo(struct file_system_type *, char *,
 	const struct super_operations *ops,
 	const struct dentry_operations *dops,
 	unsigned long);
-extern void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb);
 
 static inline void sb_mark_dirty(struct super_block *sb)
 {