ceph: fix comment, remove extraneous args

The offset/length arguments aren't used.

Signed-off-by: Sage Weil <sage@newdream.net>

net/ceph/pagevec.c

@@ -13,8 +13,7 @@
  * build a vector of user pages
  */
 struct page **ceph_get_direct_page_vector(const char __user *data,
-						 int num_pages,
-						 loff_t off, size_t len)
+					  int num_pages)
 {
 	struct page **pages;
 	int rc;