Merge the module_* device.mk files into their corresponding product mk

files.

To clean up an unnecessary indirection. Instead introduce a common file
for module products.

Test: lunch module_{arm,arm64,x86,x86_64}
      inspect the build banners
Merged-In: Ia312431a664e731f5d801ee2671f62f5cd23bd51
Change-Id: Ia312431a664e731f5d801ee2671f62f5cd23bd51