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 <[e-mail]>
Cc: [e-mail]
Acked-by: Richard Weinberger <[e-mail]>
Signed-off-by: Dominik Brodowski <[e-mail]>

fs/hostfs/hostfs.h

···
 extern int make_symlink(const char *from, const char *to);
 extern int unlink_file(const char *file);
 extern int do_mkdir(const char *file, int mode);
-extern int do_rmdir(const char *file);
+extern int hostfs_do_rmdir(const char *file);
 extern int do_mknod(const char *file, int mode, unsigned int major,
 		    unsigned int minor);
 extern int link_file(const char *from, const char *to);

fs/hostfs/hostfs_kern.c

···
 
 	if ((file = dentry_name(dentry)) == NULL)
 		return -ENOMEM;
-	err = do_rmdir(file);
+	err = hostfs_do_rmdir(file);
 	__putname(file);
 	return err;
 }

fs/hostfs/hostfs_user.c

···
 	return 0;
 }
 
-int do_rmdir(const char *file)
+int hostfs_do_rmdir(const char *file)
 {
 	int err;