armv8: ls1046aqds: Fix NAND offset for Fman ucode and env

Fix a bug of 'commit 8104deb2d6b7 ("armv8: layerscape: Adjust memory
mapping for Flash/SD card on LS1046A")' as NAND block size is 256KB
on LS1046AQDS.

Signed-off-by: Gong Qianyu <Qianyu.Gong@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/include/configs/ls1046aqds.h b/include/configs/ls1046aqds.h
index 9231cca..39bd1c3 100644
--- a/include/configs/ls1046aqds.h
+++ b/include/configs/ls1046aqds.h
@@ -435,7 +435,7 @@
 
 #ifdef CONFIG_NAND_BOOT
 #define CONFIG_ENV_SIZE			0x2000
-#define CONFIG_ENV_OFFSET		(24 * CONFIG_SYS_NAND_BLOCK_SIZE)
+#define CONFIG_ENV_OFFSET		(12 * CONFIG_SYS_NAND_BLOCK_SIZE)
 #elif defined(CONFIG_SD_BOOT)
 #define CONFIG_ENV_OFFSET		(3 * 1024 * 1024)
 #define CONFIG_SYS_MMC_ENV_DEV		0