hostfs: rename do_rmdir() to hostfs_do_rmdir()

do_rmdir() is used in the VFS layer at fs/namei.c, so use a different
name in hostfs.

Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

fs/hostfs/hostfs_kern.c

@@ -706,7 +706,7 @@ static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
 
 	if ((file = dentry_name(dentry)) == NULL)
 		return -ENOMEM;
-	err = do_rmdir(file);
+	err = hostfs_do_rmdir(file);
 	__putname(file);
 	return err;
 }