Always turn on compatible property

It's mandatory for devices launching with Android P or later.
Some makefiles still depend on PRODUCT_COMPATIBLE_PROPERTY, so rather
than aggressively removing all codes, this forces
PRODUCT_COMPATIBLE_PROPERTY to be true.

Bug: 170082975
Test: m
Change-Id: I49dab8d573c21781e6295a8581a5ad2944e165d7