ARM: tegra: remove board (but not DT) support for Paz00

Paz00 (Toshiba AC100) can be booted using device tree with equal
functionality as when booted using a board file. Remove as much of the
board file as is possible, since it's no longer needed.

One special-case is still left in board-dt-tegra20.c, since there is no
way to create a WiFi rfkill device from device tree yet. This logic is
now enabled unconditionally rather than via CONFIG_MACH_PAZ00. The extra
cases where it's enabled (.configs which did not enable Paz00 support)
shouldn't impact much since the amount of code is tiny.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-By: Marc Dietrich <marvin24@gmx.de>