orinoco_usb: fix spelling mistake in fall-through annotation

Replace "fall though" with a proper "fall through" annotation.

This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intersil/orinoco/orinoco_usb.c

@@ -911,7 +911,7 @@ static int ezusb_access_ltv(struct ezusb_priv *upriv,
 	default:
 		err("%s: Unexpected context state %d", __func__,
 		    state);
-		/* fall though */
+		/* fall through */
 	case EZUSB_CTX_REQ_TIMEOUT:
 	case EZUSB_CTX_REQ_FAILED:
 	case EZUSB_CTX_RESP_TIMEOUT: