[media] stv090x: Fix losing lock in dual DVB-S2 mode

Do not clear registers ACLC/BCLC in DVB-S2 mode for Cut <= 20.
Otherwise, the demod could lose the lock periodically.
Verified with cineS2 and Duoflex.
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/stv090x.c

@@ -2894,10 +2894,12 @@ static int stv090x_optimize_track(struct stv090x_state *state)
 		STV090x_SETFIELD_Px(reg, DVBS2_ENABLE_FIELD, 1);
 		if (STV090x_WRITE_DEMOD(state, DMDCFGMD, reg) < 0)
 			goto err;
+		if (state->internal->dev_ver >= 0x30) {
 			if (STV090x_WRITE_DEMOD(state, ACLC, 0) < 0)
 				goto err;
 			if (STV090x_WRITE_DEMOD(state, BCLC, 0) < 0)
 				goto err;
+		}
 		if (state->frame_len == STV090x_LONG_FRAME) {
 			reg = STV090x_READ_DEMOD(state, DMDMODCOD);
 			modcod = STV090x_GETFIELD_Px(reg, DEMOD_MODCOD_FIELD);