ARM: DRA7: Enable saveenv command

dra7xx_evm has eMMC and the default environment can be stored in it.
So enabling saveenv command and the configs to store environment in eMMC.

Tested on DRA752 ES1.0
Signed-off-by: NLokesh Vutla <lokeshvutla@ti.com>

include/configs/dra7xx_evm.h

@@ -14,7 +14,13 @@
 
 #define CONFIG_DRA7XX
 
-#define CONFIG_ENV_IS_NOWHERE		/* For now. */
+/* MMC ENV related defines */
+#define CONFIG_ENV_IS_IN_MMC
+#define CONFIG_SYS_MMC_ENV_DEV		1	/* SLOT2: eMMC(1) */
+#define CONFIG_ENV_OFFSET		0xE0000
+#define CONFIG_ENV_OFFSET_REDUND	(CONFIG_ENV_OFFSET + CONFIG_ENV_SIZE)
+#define CONFIG_SYS_REDUNDAND_ENVIRONMENT
+#define CONFIG_CMD_SAVEENV
 
 #define CONSOLEDEV			"ttyO0"
 #define CONFIG_CONS_INDEX		1