make_ext4fs has moved to build/target/core.mk

There's no need to add make_ext4fs to each device since it's in
build/target/core.mk since commit
720479ea7e6307648c56f61d82ac12d65f218dda

Bug: 6960586
Change-Id: Iba5228507265df698b66eff5d18b3da67a1b46b2
diff --git a/device-common.mk b/device-common.mk
index 95e1f96..ce150fe 100644
--- a/device-common.mk
+++ b/device-common.mk
@@ -78,7 +78,6 @@
     audio.a2dp.default \
     audio.usb.default \
     librs_jni \
-    make_ext4fs \
     setup_fs \
     l2ping \
     hcitool \