Revert "Set MAKEOBJDIRPREFIX for build and install world"

It seems to break 8.x

This reverts commit 670823ace0e0f49f033e0173e4533a36a2747523.
Revert "Set MAKEOBJDIRPREFIX for build and install kernel"

It seems to break 8.x

This reverts commit 2dc2f34170d629a8cc95ac5552dd506b51702e80.