media: ddbridge: remove ddb_info's from the global scope

Since the DD hardware info and maps aren't needed anymore outside of
ddbridge-hw.c (they're returned via get_ddb_info() now), mark them
static and remove all refs from ddbridge-hw.h.

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