V4L/DVB (11080): au0828: Convert to use v4l2_device/subdev framework

Convert over to using the new subdev framework for the au0828 bridge.  This
includes using the new i2c probing mechanism.

Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>