media: dvb-frontends/stv0367: DDB frontend status inquiry fixup

Return 0 instead of -EINVAL in get_frontend if no demod mode is active.
This fixes ie. dvb-fe-tool getting confused and assuming a DVBv3 FE on idle
frontends when the FE has been put to sleep using sleep().

Also, in read_status(), don't immediately return when no demod is active,
so the remaining code has a chance to clear the signal statistics.
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-frontends/stv0367.c

@@ -3090,7 +3090,7 @@ static int stv0367ddb_read_status(struct dvb_frontend *fe,
 {
 	struct stv0367_state *state = fe->demodulator_priv;
 	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
-	int ret;
+	int ret = 0;
 
 	switch (state->activedemod) {
 	case demod_ter:
@@ -3100,7 +3100,7 @@ static int stv0367ddb_read_status(struct dvb_frontend *fe,
 		ret = stv0367cab_read_status(fe, status);
 		break;
 	default:
-		return 0;
+		break;
 	}
 
 	/* stop and report on *_read_status failure */
@@ -3138,7 +3138,7 @@ static int stv0367ddb_get_frontend(struct dvb_frontend *fe,
 		break;
 	}
 
-	return -EINVAL;
+	return 0;
 }
 
 static int stv0367ddb_sleep(struct dvb_frontend *fe)