tacoma: Build a mmc-ext4-tar image

The mmc-ext4-tar image is used for MMC code updates.

Change-Id: I61f27281a2ab89cceb956f6b4076535b0287a36a
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 765c068..4d94d9e 100644
--- a/meta-witherspoon/conf/machine/witherspoon-tacoma.conf
+++ b/meta-witherspoon/conf/machine/witherspoon-tacoma.conf
@@ -2,7 +2,7 @@
 UBOOT_MACHINE = "ast2600_openbmc_defconfig"
 UBOOT_DEVICETREE = "ast2600-tacoma"
 
-IMAGE_FSTYPES += "ext4"
+IMAGE_FSTYPES += "ext4 mmc-ext4-tar"
 
 OBMC_POWER_SUPPLY_INSTANCES = "0 1"