swift.conf: Build an ext4 image

Build an ext4 image for swift to be used in its eMMC chip.

Tested: An ext4 image was built in addition to the current ubi ones.

Change-Id: Ifd546d9604309853ec4da06b8e34699ecc296a70
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-witherspoon/conf/machine/swift.conf b/meta-witherspoon/conf/machine/swift.conf
index bca1ed3..077d0b5 100644
--- a/meta-witherspoon/conf/machine/swift.conf
+++ b/meta-witherspoon/conf/machine/swift.conf
@@ -1,5 +1,7 @@
 require conf/machine/witherspoon.conf
 
+IMAGE_FSTYPES += "ext4"
+
 KERNEL_DEVICETREE = "${KMACHINE}-bmc-opp-${MACHINE}.dtb"
 
 PHOSPHOR_MRW_LICENSE = "Apache-2.0"