[media] af9033: continue polling unless critical IO error

That case is not IO error, so better to jump out now, but still
continue polling.

Cc: Bimow Chen <[e-mail]>
Signed-off-by: Antti Palosaari <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/dvb-frontends/af9033.c

···
 			snr_val *= 2;
 			break;
 		default:
-			goto err;
+			goto err_schedule_delayed_work;
 		}
 
 		/* read current modulation */