tegra: whistler: store environment in eMMC

Store the environment in eMMC, at the end of the second boot sector.
This should not conflict with any other eMMC usage: U-Boot is stored
well below this location, and the kernel only uses the general area
of the eMMC once booted, not the boot sectors.

Note: This assumes the user plugged the standard 8MB MoviNAND card into
J29/HSMMC/POP. If they didn't, the boot sector layout may be different.
However, use of that particular card is standard practice as far as I
know.

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

include/configs/whistler.h

@@ -66,8 +66,15 @@
 #define CONFIG_CMD_EXT2
 #define CONFIG_CMD_FAT
 
-/* Environment not stored */
-#define CONFIG_ENV_IS_NOWHERE
+/*
+ * Environment in eMMC, at the end of 2nd "boot sector". Note: This assumes
+ * the user plugged the standard 8MB MoviNAND card into J29/HSMMC/POP. If
+ * they didn't, the boot sector layout may be different. However, use of that
+ * particular card is standard practice as far as I know.
+ */
+#define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_ENV_OFFSET ((2 * 512 * 1024) - CONFIG_ENV_SIZE)
+#define CONFIG_SYS_MMC_ENV_DEV 0
 
 /* USB Host support */
 #define CONFIG_USB_EHCI