[media] mb86a20s: make AGC work better

It is recommented to change register 0x0440 value to 0, in order
to fix some AGC bug.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb-frontends/mb86a20s.c

@@ -126,7 +126,8 @@ static struct regdata mb86a20s_init[] = {
 	{ 0x50, 0xd7 }, { 0x51, 0x3f },
 	{ 0x28, 0x74 }, { 0x29, 0x00 }, { 0x28, 0x74 }, { 0x29, 0x40 },
 	{ 0x28, 0x46 }, { 0x29, 0x2c }, { 0x28, 0x46 }, { 0x29, 0x0c },
-	{ 0x04, 0x40 }, { 0x05, 0x01 },
+
+	{ 0x04, 0x40 }, { 0x05, 0x00 },
 	{ 0x28, 0x00 }, { 0x29, 0x10 },
 	{ 0x28, 0x05 }, { 0x29, 0x02 },
 	{ 0x1c, 0x01 },