get rid of 'parent' argument of ->d_compare()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 98044a8..107d9ab 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -130,7 +130,7 @@
 	int (*d_revalidate)(struct dentry *, unsigned int);
 	int (*d_weak_revalidate)(struct dentry *, unsigned int);
 	int (*d_hash)(const struct dentry *, struct qstr *);
-	int (*d_compare)(const struct dentry *, const struct dentry *,
+	int (*d_compare)(const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(const struct dentry *);
 	int (*d_init)(struct dentry *);