gui/math/gralloc: Set min_sdk_version

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

Bug: 152655956
Test: m
Change-Id: Ib7685f5f4f924ac145eb4f10ad83a6c0548b2206