serial: 8250_early: Add earlycon support for Tegra

Declare an OF early console for Tegra so that the early console device
can be specified via the "stdout-path" property in device-tree.
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_early.c

@@ -149,6 +149,7 @@ EARLYCON_DECLARE(uart8250, early_serial8250_setup);
 EARLYCON_DECLARE(uart, early_serial8250_setup);
 OF_EARLYCON_DECLARE(ns16550, "ns16550", early_serial8250_setup);
 OF_EARLYCON_DECLARE(ns16550a, "ns16550a", early_serial8250_setup);
+OF_EARLYCON_DECLARE(uart, "nvidia,tegra20-uart", early_serial8250_setup);
 
 #ifdef CONFIG_SERIAL_8250_OMAP