[media] dib0700: properly setup GPIOs for PCTV 340e

Provide a frontend setup routine for the PCTV 340e which takes into account
the specific GPIO setup of the board.

Note that this patch does *not* take into account the xc4000 reset pin, which
is attached to the dib7000.

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Cc: Patrick Boettcher <pboettcher@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>