tegra: enable bootz command

bootz is just like bootm, except that it can boot a raw zImage, without
requiring it to be wrapped inside a uImage.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NTom Warren <twarren@nvidia.com>

include/configs/tegra2-common.h

@@ -194,4 +194,5 @@
 #define CONFIG_TEGRA_GPIO
 #define CONFIG_CMD_GPIO
 #define CONFIG_CMD_ENTERRCM
+#define CONFIG_CMD_BOOTZ
 #endif /* __TEGRA2_COMMON_H */