tegra: Add support for UART init in cpu board.c

We add a way of initialising the selected of UARTs prior to relocation.
Boards can use the board_init_uart_f() instead of repeating this code
themselves.

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