Convert Vehicle Property to integer

This make sense for easier extending Vehicle Hal interface
by OEMs and creating new versions.

Test: adb shell "su system /data/nativetest/android.hardware.vehicle@2.0-manager-unit-tests/android.hardware.vehicle@2.0-manager-unit-tests" ; ENABLE_TREBLE=true make vts BUILD_GOOGLE_VTS=true -j32 && vts-tradefed run commandAndExit vts --skip-all-system-status-check --primary-abi-only --skip-preconditions --module VehicleHidlTest -l INFO

Change-Id: I02415a1c180a6d24fded48a1583f7cb150419820
Fix: b/34894217
diff --git a/vehicle/2.0/IVehicle.hal b/vehicle/2.0/IVehicle.hal
index cab6ce0..dc13089 100644
--- a/vehicle/2.0/IVehicle.hal
+++ b/vehicle/2.0/IVehicle.hal
@@ -32,7 +32,7 @@
    * StatusCode::INVALID_ARG, otherwise a list of vehicle property
    * configurations with StatusCode::OK
    */
-  getPropConfigs(vec<VehicleProperty> props)
+  getPropConfigs(vec<int32_t> props)
           generates (StatusCode status, vec<VehiclePropConfig> propConfigs);
 
   /**
@@ -84,7 +84,7 @@
    * If this client wasn't subscribed to the given property, this method
    * must return StatusCode::INVALID_ARG.
    */
-  unsubscribe(IVehicleCallback callback, VehicleProperty propId)
+  unsubscribe(IVehicleCallback callback, int32_t propId)
           generates (StatusCode status);
 
   /**