hardware/libhardware: convert LOCAL_MODULE_PATH to LOCAL_MODULE_RELATIVE_PATH

LOCAL_MODULE_PATH doesn't work for multiarch builds, replace it
with LOCAL_MODULE_RELATIVE_PATH.

Change-Id: I4e4ceec61d026bbe74ba604554c06104bde42e5e
diff --git a/modules/usbaudio/Android.mk b/modules/usbaudio/Android.mk
index 6b5e66d..199eb09 100644
--- a/modules/usbaudio/Android.mk
+++ b/modules/usbaudio/Android.mk
@@ -17,7 +17,7 @@
 include $(CLEAR_VARS)
 
 LOCAL_MODULE := audio.usb.default
-LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
+LOCAL_MODULE_RELATIVE_PATH := hw
 LOCAL_SRC_FILES := \
 	audio_hw.c
 LOCAL_C_INCLUDES += \