V4L/DVB (13974): [STV090x] Fix locking reliabilty issues in automatic mode.

In automatic S/S2 detection mode, locking of a DVB-S transponder could
fail when coming from a DVB-S2 transponder. This change fixes the issue
by first disabling DVB-S and DVB-S2 mode before enabling it again.
Signed-off-by: NAndreas Regel <andreas.regel@gmx.de>
Signed-off-by: NManu Abraham <manu@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/stv090x.c

@@ -1246,6 +1246,10 @@ static int stv090x_delivery_search(struct stv090x_state *state)
 	default:
 		/* enable DVB-S2 and DVB-S2 in Auto MODE */
 		reg = STV090x_READ_DEMOD(state, DMDCFGMD);
+		STV090x_SETFIELD_Px(reg, DVBS1_ENABLE_FIELD, 0);
+		STV090x_SETFIELD_Px(reg, DVBS2_ENABLE_FIELD, 0);
+		if (STV090x_WRITE_DEMOD(state, DMDCFGMD, reg) < 0)
+			goto err;
 		STV090x_SETFIELD_Px(reg, DVBS1_ENABLE_FIELD, 1);
 		STV090x_SETFIELD_Px(reg, DVBS2_ENABLE_FIELD, 1);
 		if (STV090x_WRITE_DEMOD(state, DMDCFGMD, reg) < 0)