ARM: tegra: convert tegra to use distro defaults

Modify all Tegra boards to include the "distro defaults" header, so that
all the config options distros expect are enabled. Remove any #defines
that enable the same options from the Tegra files.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>