u-boot-aspeed: Generate default env for eMMC

Generate a default environment to boot an eMMC based on a txt
file. Populate the generated environment image into the eMMC.

Change-Id: I9d4a68decb93a51ec4419c0491ae020f647692af
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/wic/emmc-aspeed.wks.in b/wic/emmc-aspeed.wks.in
index 8163521..ace5f47 100644
--- a/wic/emmc-aspeed.wks.in
+++ b/wic/emmc-aspeed.wks.in
@@ -21,7 +21,7 @@
 
 bootloader --ptable gpt
 
-part --align 4 --fixed-size 1M --label u-boot-env
+part --align 4 --fixed-size 1M --source rawcopy --sourceparams="file=${DEPLOY_DIR_IMAGE}/u-boot-env.bin"
 part --fstype=ext4 --fixed-size 64M --source bootimg-partition --label boot-a
 part --fstype=ext4 --fixed-size 64M --source bootimg-partition --label boot-b
 part --fstype=ext4 --fixed-size 1G --source rootfs --label rofs-a