Include core makefile before device-specific one.

The reverse order (car-specific makefile before the core one) causes
incorrect order of jars in the PRODUCT_SYSTEM_SERVER_JARS variable.
Namely, the car-specific jar 'car-framework-service' comes before the
core jar 'services'. This order is problematic for the build system,
because 'car-framework-service' depends on 'services'.

Test: $(ANDROID_BUILD_TOP)/vendor/google/build/build_test.bash --dist --incremental --shard-count=3 --shard=2
Test: lunch aosp_car_arm    && m
Test: lunch aosp_car_arm64  && m
Test: lunch aosp_car_x86    && m
Test: lunch aosp_car_x86_64 && m
Test: lunch car_x86_64      && m

Change-Id: Iafb4d62c177eff5b15d28a4f0e55f027c55c9861