arm: Tegra2: GPIO: enable GPIO for Tegra2 boards

Signed-off-by: Tom Warren <twarren@nvidia.com>

include/configs/tegra2-common.h

@@ -160,4 +160,6 @@
 						CONFIG_SYS_INIT_RAM_SIZE - \
 						GENERATED_GBL_DATA_SIZE)
 
+#define CONFIG_TEGRA2_GPIO
+#define CONFIG_CMD_GPIO
 #endif /* __TEGRA2_COMMON_H */