ARM: tegra: Add support for nyan-big board

Nyan-big is a Tegra124 clamshell board that is very similar to venice2, but
it has a different panel, the sdcard cd and wp sense are flipped, and it has
a different revision of the AS3722 PMIC.

This is the Acer Chromebook 13 CB5-311-T7NN (13.3-inch HD, NVIDIA
Tegra K1, 2GB). The display is not currently supported, so it should
boot on other nyan-based Chromebooks also, but only the device tree for
nyan-big is provided here.

The device tree file is from Linux but with features removed which are
unlikely to be supported in U-Boot soon (regulators, pinmux). Also the
addresses are updated to 32-bit.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
(rebase, change to 'nyan-big', fix pinmux that resets nyan-big)