imx: mx6: Change ENV offset to 512K bytes for larger u-boot image

To align with other mx6 boards, change ENV offset from 384KB to
512KB position to fit a larger u-boot image.

Signed-off-by: Ye.Li <B37916@freescale.com>

include/configs/mx6slevk.h

@@ -198,7 +198,7 @@
 #define CONFIG_ENV_SPI_MODE             CONFIG_SF_DEFAULT_MODE
 #define CONFIG_ENV_SPI_MAX_HZ           CONFIG_SF_DEFAULT_SPEED
 #else
-#define CONFIG_ENV_OFFSET		(6 * SZ_64K)
+#define CONFIG_ENV_OFFSET		(8 * SZ_64K)
 #define CONFIG_ENV_IS_IN_MMC
 #endif
 

include/configs/mx6sxsabresd.h

@@ -260,7 +260,7 @@
 #define FSL_QSPI_FLASH_NUM		2
 #endif
 
-#define CONFIG_ENV_OFFSET		(6 * SZ_64K)
+#define CONFIG_ENV_OFFSET		(8 * SZ_64K)
 #define CONFIG_ENV_SIZE			SZ_8K
 #define CONFIG_ENV_IS_IN_MMC