ARM: tegra: Add p2371-0000 board

P2371-0000 is a P2581 or P2530 CPU board married to a P2595 I/O
board. The combination contains SoC, DRAM, eMMC, SD card slot,
HDMI, USB micro-B port, Ethernet via USB3, USB3 host port, SATA,
a GPIO expansion header, and an analog audio jack.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>