media: ddbridge/max: rename ddbridge-maxs8.[c|h] to ddbridge-max.[c|h]

Rename the MaxS4/8 support files following upstream. References to these
files and descriptions have been updated aswell.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>