Tegra30: Add AVP (arm720t) files

This provides SPL support for T30 boards - AVP early init, plus
CPU (A9) init/jump to main U-Boot.

Some changes were made to Tegra20 cpu.c to move common routines
into tegra-common/cpu.c and reduce code duplication.

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