Remove ultrasound system properties.

Using config.xml in lieu of system properties. See b/21072209

Bug: 21072209

Change-Id: I709b752dbc3155be78af363db244c6d51fe1696e
diff --git a/device.mk b/device.mk
index 5cda914..b3f0381 100644
--- a/device.mk
+++ b/device.mk
@@ -342,11 +342,6 @@
     persist.audio.fluence.voicerec=false \
     persist.audio.fluence.speaker=false
 
-# Near-ultrasound support in the default audio and speaker paths.
-PRODUCT_PROPERTY_OVERRIDES += \
-    persist.audio.spkr.ultrasound=true \
-    persist.audio.mic.ultrasound=true
-
 # Setup custom emergency number list based on the MCC. This is needed by RIL
 PRODUCT_PROPERTY_OVERRIDES += \
     persist.radio.custom_ecc=1