add support for module supported or unsupported target architectures

Add four new variables for module makefiles:

LOCAL_MODULE_TARGET_ARCH specifies that a module is only supported for
one or more architectures.  Any architecture not in the list will be
not attempt to build the module.  The expected use case is prebuilts
that are only suitable for a single architecture, or modules like llvm
that need per-architecture support.

LOCAL_MODULE_UNSUPPORTED_TARGET_ARCH specifies that a module cannot be
built for one or more architectures.

LOCAL_MODULE_TARGET_ARCH_WARN and LOCAL_MODULE_UNSUPPORTED_TARGET_ARCH_WARN
are the same, but warn that the arch is not supported, which is useful
for modules that are critical but not yet working.

The logic for whether or not to build an architecture is fairly
complicated, so this patch consolidates it into module_arch_supported.mk

Change-Id: I120caf4a375f484e1fd6017b60c2f53882ae01e6