rsi: add missing endpoint sanity checks

The driver expects at least one bulk-in endpoint when in "wifi-alone"
operating mode and two bulk-in endpoints otherwise, and would otherwise
fail to to submit the corresponding bulk URB to the default pipe during
probe with a somewhat cryptic message:

	rsi_91x: rsi_rx_urb_submit: Failed in urb submission
	rsi_91x: rsi_probe: Failed in probe...Exiting
	RSI-USB WLAN: probe of 2-2.4:1.0 failed with error -8

The current endpoint sanity check looks broken and would only bail out
early if there was no bulk-in endpoint but at least one bulk-out
endpoint.

Tighten this check to always require at least one bulk-in and one
bulk-out endpoint, and add the missing sanity check for a Bluetooth
bulk-in endpoint when in a BT operating mode. Also make sure to log an
informative error message when the expected endpoints are missing.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_usb.c

@@ -149,9 +149,17 @@ static int rsi_find_bulk_in_and_out_endpoints(struct usb_interface *interface,
 			break;
 	}
 
-	if (!(dev->bulkin_endpoint_addr[0]) &&
-	    dev->bulkout_endpoint_addr[0])
+	if (!(dev->bulkin_endpoint_addr[0] && dev->bulkout_endpoint_addr[0])) {
+		dev_err(&interface->dev, "missing wlan bulk endpoints\n");
 		return -EINVAL;
+	}
+
+	if (adapter->priv->coex_mode > 1) {
+		if (!dev->bulkin_endpoint_addr[1]) {
+			dev_err(&interface->dev, "missing bt bulk-in endpoint\n");
+			return -EINVAL;
+		}
+	}
 
 	return 0;
 }