IB/mthca: Make functions that never fail return void

The function mthca_free_err_wqe() can never fail, so get rid of its
return value.  That means handle_error_cqe() doesn't have to check
what mthca_free_err_wqe() returns, which means it can't fail either
and doesn't have to return anything either.  All this results in
simpler source code and a slight object code improvement:

add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-10 (-10)
function                                     old     new   delta
mthca_free_err_wqe                            83      81      -2
mthca_poll_cq                               1758    1750      -8

Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index fba608e..79245717 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -2182,8 +2182,8 @@
 	return err;
 }
 
-int mthca_free_err_wqe(struct mthca_dev *dev, struct mthca_qp *qp, int is_send,
-		       int index, int *dbd, __be32 *new_wqe)
+void mthca_free_err_wqe(struct mthca_dev *dev, struct mthca_qp *qp, int is_send,
+			int index, int *dbd, __be32 *new_wqe)
 {
 	struct mthca_next_seg *next;
 
@@ -2193,7 +2193,7 @@
 	 */
 	if (qp->ibqp.srq) {
 		*new_wqe = 0;
-		return 0;
+		return;
 	}
 
 	if (is_send)
@@ -2207,8 +2207,6 @@
 			(next->ee_nds & cpu_to_be32(0x3f));
 	else
 		*new_wqe = 0;
-
-	return 0;
 }
 
 int __devinit mthca_init_qp_table(struct mthca_dev *dev)