rds: signedness bug

In the original code if the copy_from_user() fails in rds_rdma_pages()
then the error handling fails and we get a stack trace from kmalloc().

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 4806467..1a41deb 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -522,7 +522,7 @@
 	struct rds_rdma_args *args;
 	struct rds_iovec vec;
 	struct rm_rdma_op *op = &rm->rdma;
-	unsigned int nr_pages;
+	int nr_pages;
 	unsigned int nr_bytes;
 	struct page **pages = NULL;
 	struct rds_iovec __user *local_vec;