Disable module build rules when using prebuilts.

Re-enable the rules when MODULE_BUILD_FROM_SOURCE is true.
This is a workaround for the fact that we don't have proper
separation between prebuilts and source.

Bug: 192556458
Test: m
Merged-In: Icc7193288b9b3f2a62a9b29d67fd0661e3443825

Change-Id: I83e011106ef063c489ac9cc040aff15cc9a73450
3 files changed