platform/chrome: cros_ec_proto: Fix spelling mistake "unknwon" -> "unknown"

There is a spelling mistake in a dev_dbg message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220614064909.47804-1-colin.i.king@gmail.com

drivers/platform/chrome/cros_ec_proto.c

@@ -346,7 +346,7 @@ static int cros_ec_get_proto_info(struct cros_ec_device *ec_dev, int devidx)
 		dev_dbg(ec_dev->dev, "found PD chip\n");
 		break;
 	default:
-		dev_dbg(ec_dev->dev, "unknwon passthru index: %d\n", devidx);
+		dev_dbg(ec_dev->dev, "unknown passthru index: %d\n", devidx);
 		break;
 	}