tegra: Implement gpio_early_init() on Tamonten

The PI4 GPIO is used on Tamonten to reset carrier board peripherals.
Power sequencing hardware on the carrier pulls the reset low before
powering up the Tegra, and the CPU is supposed to signal readiness,
and therefore bring peripherals out of reset by pulling PI4 high.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

board/avionic-design/common/tamonten.c

@@ -49,6 +49,14 @@ void gpio_config_uart(void)
 {
 }
 
+#ifdef CONFIG_BOARD_EARLY_INIT_F
+void gpio_early_init(void)
+{
+	gpio_request(GPIO_PI4, NULL);
+	gpio_direction_output(GPIO_PI4, 1);
+}
+#endif
+
 #ifdef CONFIG_TEGRA2_MMC
 /*
  * Routine: pin_mux_mmc