allscenarios-image-common.inc: Drop ZFS workaround

This was a ZFS specific workaround. Drop because it makes little sense
to grow the fs this much for all other no-zfs hosts.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

meta-ohos-core/recipes-core/images/allscenarios-image-common.inc

@@ -12,7 +12,3 @@ IMAGE_INSTALL_append = "\
 			packagegroup-ble-essentials \
 			gdbserver \
 			"
-
-# This is a workaround in case the build runs on ZFS with compression on.
-# It also gives us extra runtime space.
-IMAGE_OVERHEAD_FACTOR = "2"