tegra: Remove tegra_spl_gpio_direction_output declaration from header file

This function is deleted by commit 2fccd2d96b
"tegra: Convert tegra GPIO driver to use driver model".

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/include/asm/arch-tegra/gpio.h

@@ -28,15 +28,6 @@ struct tegra_gpio_config {
 };
 
 /**
- * tegra_spl_gpio_direction_output() - set the output value of a GPIO
- *
- * This function is only used from SPL on seaboard, which needs to enable a
- * GPIO to get the UART running. It could be done in U-Boot rather than SPL,
- * but for now, this gets it working
- */
-int tegra_spl_gpio_direction_output(int gpio, int value);
-
-/**
  * Configure a list of GPIOs
  *
  * @param config	List of GPIO configurations