openharmony: Initial support for building on 64-bit targets and qemuarm-efi

This makes meta-openharmony compile for the qemuarm64, qemuarm64-efi, qemuarm-efi and raspberrypi4-64 target MACHINEs.

Signed-off-by: Bernhard Rosenkränzer bernhard.rosenkraenzer.ext@huawei.com

Closes eclipse/oniro-core/meta-openharmony#56 and eclipse/oniro-core/meta-openharmony#49