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: Ibc3d93454ebd8b943a500d51653d8c3cee6da48a
1 file changed