media: ddbridge: change MCI base ID and define a SX8 ID

Change the start of the MCI ID range (internally used only) to 48 and
define an ID for the SX8 card type. Use this new ID to handle device
attachment.

This change is done in preparation for support of more MCI based cards.

Picked up from the upstream dddvb GIT.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>