media: ddbridge: move modparams to ddbridge-core.c

Besides the 'msi' module option, all options are used from within
ddbridge-core only, so move them over from ddbridge-main, and declare the
associated variables static. Since the prototypes in ddbridge.h aren't
necessary anymore now, remove them. As a side effect, this has the benefit
of aligning things more with the dddvb upstream.

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