mwifiex: prevent corruption instead of just warning

Probably we never hit this condition, but in case we do, we may as
well put a return here instead of just printing a warning message and
then corrupting memory.  The caller doesn't check the return code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/pcie.c

@@ -1228,9 +1228,12 @@ static int mwifiex_pcie_event_complete(struct mwifiex_adapter *adapter,
 	if (!skb)
 		return 0;
 
-	if (rdptr >= MWIFIEX_MAX_EVT_BD)
+	if (rdptr >= MWIFIEX_MAX_EVT_BD) {
 		dev_err(adapter->dev, "event_complete: Invalid rdptr 0x%x\n",
 					rdptr);
+		ret = -EINVAL;
+		goto done;
+	}
 
 	/* Read the event ring write pointer set by firmware */
 	if (mwifiex_read_reg(adapter, REG_EVTBD_WRPTR, &wrptr)) {