tacoma: Build a wic image

Build a wic image with the zImage and device tree in the
/boot partition. Rename the device tree to aspeed-bmc.dtb
so that it's generic instead of having the machine name in
the file.

Change-Id: I7ed561dc1122c3830b0ab9946a48f12a65e4ce34
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-witherspoon/conf/machine/witherspoon-tacoma.conf b/meta-witherspoon/conf/machine/witherspoon-tacoma.conf
index 4d94d9e..774f127 100644
--- a/meta-witherspoon/conf/machine/witherspoon-tacoma.conf
+++ b/meta-witherspoon/conf/machine/witherspoon-tacoma.conf
@@ -2,7 +2,9 @@
 UBOOT_MACHINE = "ast2600_openbmc_defconfig"
 UBOOT_DEVICETREE = "ast2600-tacoma"
 
-IMAGE_FSTYPES += "ext4 mmc-ext4-tar"
+IMAGE_FSTYPES += "wic.xz mmc-ext4-tar"
+KERNEL_IMAGETYPES += "zImage"
+IMAGE_BOOT_FILES = "zImage ${KERNEL_DEVICETREE};aspeed-bmc.dtb"
 
 OBMC_POWER_SUPPLY_INSTANCES = "0 1"