build: Remove android makefiles from upstream modules.

These makefiles don't really belong upstream since they contain specific
references to things in the mupen64plus-ae project (e.g. ae-bridge).

One less diff with upstream, one less need to fork.
(wip glide)
(wip rice)
(wip gln64)
(wip bridge/front)
assets: Add polygon offset settings to gln64.conf.