Changed car emulator target to use _audio_zone_

Changed car emulator audio to use _audio_zone_ to identify the audio
zone for each zone device.

Bug: 148292262
Test: Lunch gcar_hl_md_emu_x86
Test: make -j60
Test: emulator
Change-Id: I51c0ae2d24b1343dd2568f88bc19b635f5275379
3 files changed