libfs: kill empty_dir_getattr()

It's used only to initialize ->getattr in one inode_operations instance
(empty_dir_inode_operations) and its behaviour had always been equivalent
to what we get with NULL ->getattr.

Just remove that initializer, along with empty_dir_getattr() itself.
While we are at it, the same instance has ->permission initialized to
generic_permission, which is what NULL ->permission ends up doing.
Again, no point keeping it.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

fs/libfs.c

@@ -1711,15 +1711,6 @@ static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry,
 	return ERR_PTR(-ENOENT);
 }
 
-static int empty_dir_getattr(struct mnt_idmap *idmap,
-			     const struct path *path, struct kstat *stat,
-			     u32 request_mask, unsigned int query_flags)
-{
-	struct inode *inode = d_inode(path->dentry);
-	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
-	return 0;
-}
-
 static int empty_dir_setattr(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct iattr *attr)
 {
@@ -1733,9 +1724,7 @@ static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t siz
 
 static const struct inode_operations empty_dir_inode_operations = {
 	.lookup		= empty_dir_lookup,
-	.permission	= generic_permission,
 	.setattr	= empty_dir_setattr,
-	.getattr	= empty_dir_getattr,
 	.listxattr	= empty_dir_listxattr,
 };