ARM: tegra20: add funcmux for exposing UART over uSD slot on Tegra 20

UART-A can be exposed through uSD, this was tested on Transformer T20
but should work on all Ventana-based boards.

TX is exported on SDD pingroup corresponding to uSD CLK pin
RX is exported on SDB which is CMD pin in uSD slot

Signed-off-by: Artur Kowalski <arturkow2000@gmail.com>
Reviewed-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
4 files changed