Audio HAL now uses hal.mk

Renames Android.mk to be hal.mk.
This requires a change in device/generic/google

BUG=none
Change-Id: I4a5aabd76bd02d35ba6a7f06652f9db6a20819e0
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
diff --git a/peripheral/audio/usb/Android.mk b/peripheral/audio/usb/hal.mk
similarity index 100%
rename from peripheral/audio/usb/Android.mk
rename to peripheral/audio/usb/hal.mk