[media] m88ds3103: add default value for reg 56

Reg 0x56 should be programmed to 0x01. Add default to inittab.

Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>