fix locking in efi_secret_unlink()

We used to need securityfs_remove() to undo simple_pin_fs() done when
the file had been created and to drop the second extra reference
taken at the same time.  Now that neither is needed (or done by
securityfs_remove()), we can simply call simple_unlink() and be done
with that - the broken games with locking had been there only for the
sake of securityfs_remove().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

drivers/virt/coco/efi_secret/efi_secret.c

@@ -136,15 +136,7 @@ static int efi_secret_unlink(struct inode *dir, struct dentry *dentry)
 		if (s->fs_files[i] == dentry)
 			s->fs_files[i] = NULL;
 
-	/*
-	 * securityfs_remove tries to lock the directory's inode, but we reach
-	 * the unlink callback when it's already locked
-	 */
-	inode_unlock(dir);
-	securityfs_remove(dentry);
-	inode_lock(dir);
-
-	return 0;
+	return simple_unlink(inode, dentry);
 }
 
 static const struct inode_operations efi_secret_dir_inode_operations = {