NFS: Fix the return value in nfs_page_mkwrite()

Commit c2ec175c39f62949438354f603f4aa170846aabb ("mm: page_mkwrite
change prototype to match fault") exposed a bug in the NFS
implementation of page_mkwrite.  We should be returning 0 on success...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nfs/file.c

@@ -516,8 +516,6 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 		goto out_unlock;
 
 	ret = nfs_updatepage(filp, page, 0, pagelen);
-	if (ret == 0)
-		ret = pagelen;
 out_unlock:
 	unlock_page(page);
 	if (ret)