arm/tegra: Split Seaboard GPIO table to allow for Ventana

Seaboard and Ventana share some GPIOs, but others are different. Split the
GPIO table into common, seaboard-specific, and ventana-specific tables, so
that only the correct ones are enabled for each board. Add a few missing
audio-related GPIOs for Ventana.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>