Drop redundant inclusion of USB audio HAL

device/qcom/common includes audio.usb.default by default already, so
it's not needed to include it here as well.

As of now, USB audio support is dropped completely from the build,
because it is not fully supported. See also
I01057c151bc6738073412444c2a9581131aeb0cb in device/qcom/common and
related changes.

Issue: FP2P-478
Change-Id: Ic92735c36d3ac8f373c90e3676faf3ab059d0560
diff --git a/device.mk b/device.mk
index 5612495..58af73e 100644
--- a/device.mk
+++ b/device.mk
@@ -271,7 +271,6 @@
 	audio.a2dp.default \
 	audio.primary.msm8974 \
 	audio.r_submix.default \
-	audio.usb.default \
 	audio_policy.msm8974 \
 	libqcompostprocbundle \
 	libqcomvisualizer \