media: dvb-frontends: lgdt3306a.c: remove dead code

Fix the following coccinelle report:

drivers/media/dvb-frontends/lgdt3306a.c:718:5-8:
Unneeded variable: "ret". Return "0" on line 744

Code was enclosed with #if 0 and thus this variable was not needed.
Remove that function altogether.

The  lgdt3306a_spectral_inversion function was dropped completely
since the function doesn't do anything. A comment was left at its
calling site to let others know that spectral_inversion defaults
already set for VSB and QAM

Found using - Coccinelle (http://coccinelle.lip6.fr)

Link: https://lore.kernel.org/linux-media/20200903131311.442255-1-dwlsalmeida@gmail.comSigned-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/dvb-frontends/lgdt3306a.c

@@ -711,39 +711,6 @@ static int lgdt3306a_set_inversion_auto(struct lgdt3306a_state *state,
 	return ret;
 }
 
-static int lgdt3306a_spectral_inversion(struct lgdt3306a_state *state,
-				       struct dtv_frontend_properties *p,
-				       int inversion)
-{
-	int ret = 0;
-
-	dbg_info("(%d)\n", inversion);
-#if 0
-	/*
-	 * FGR - spectral_inversion defaults already set for VSB and QAM;
-	 * can enable later if desired
-	 */
-
-	ret = lgdt3306a_set_inversion(state, inversion);
-
-	switch (p->modulation) {
-	case VSB_8:
-		/* Manual only for VSB */
-		ret = lgdt3306a_set_inversion_auto(state, 0);
-		break;
-	case QAM_64:
-	case QAM_256:
-	case QAM_AUTO:
-		/* Auto ok for QAM */
-		ret = lgdt3306a_set_inversion_auto(state, 1);
-		break;
-	default:
-		ret = -EINVAL;
-	}
-#endif
-	return ret;
-}
-
 static int lgdt3306a_set_if(struct lgdt3306a_state *state,
 			   struct dtv_frontend_properties *p)
 {
@@ -1048,8 +1015,8 @@ static int lgdt3306a_set_parameters(struct dvb_frontend *fe)
 	if (lg_chkerr(ret))
 		goto fail;
 
-	ret = lgdt3306a_spectral_inversion(state, p,
-					state->cfg->spectral_inversion ? 1 : 0);
+	/* spectral_inversion defaults already set for VSB and QAM */
+
 	if (lg_chkerr(ret))
 		goto fail;