Mark libbluetooth-types as vendor_available

libbluetooty-types is used by a vendor module
android.hardware.bluetooth@1.0-service.sim, thus marking it as
vendor_available so that the lib is allowed for the HAL service when
building with BOARD_VNDK_VERSION.

Bug: 37342627
Test: BOARD_VNDK_VERSION=current m -j
android.hardware.bluetooth@1.0-service.sim

Change-Id: I39d071fc249ce6842e7175751abd6249b9367231