Add Mega_device configuration option

This lets you configure soong to build for every supported architecture
in one build. Installation is disabled, since it's not actually setting
up multiple devices, and would try to install multiple versions to a
single path.

Configurations that do not build are commented out.

Change-Id: I92ddea0b9ddbd53e12187c7f581b8ac5bd5fdec3
3 files changed