media: cxusb, dib0700: ignore XC2028_I2C_FLUSH

The XC2028_I2C_FLUSH only needs to be implemented on a few
devices. Others can safely ignore it.

That prevents filling the dmesg with lots of messages like:

	dib0700: stk7700ph_xc3028_callback: unknown command 2, arg 0

Cc: stable@vger.kernel.org
Fixes: 4d37ece7 ("[media] tuner/xc2028: Add I2C flush callback")
Reported-by: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/dvb-usb/cxusb.c

@@ -679,6 +679,8 @@ static int dvico_bluebird_xc2028_callback(void *ptr, int component,
 	case XC2028_RESET_CLK:
 		deb_info("%s: XC2028_RESET_CLK %d\n", __func__, arg);
 		break;
+	case XC2028_I2C_FLUSH:
+		break;
 	default:
 		deb_info("%s: unknown command %d, arg %d\n", __func__,
 			 command, arg);

drivers/media/usb/dvb-usb/dib0700_devices.c

@@ -433,6 +433,7 @@ static int stk7700ph_xc3028_callback(void *ptr, int component,
 		state->dib7000p_ops.set_gpio(adap->fe_adap[0].fe, 8, 0, 1);
 		break;
 	case XC2028_RESET_CLK:
+	case XC2028_I2C_FLUSH:
 		break;
 	default:
 		err("%s: unknown command %d, arg %d\n", __func__,