hostfs_open(): don't open-code file_dentry()

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

fs/hostfs/hostfs_kern.c

@@ -317,7 +317,7 @@ retry:
 	if (mode & FMODE_WRITE)
 		r = w = 1;
 
-	name = dentry_name(d_real(file->f_path.dentry, file->f_inode));
+	name = dentry_name(file_dentry(file));
 	if (name == NULL)
 		return -ENOMEM;