Add HD Audio device to guest via config

lib/vm-run

@@ -192,6 +192,7 @@ vm::run(){
     vm::bhyve_device_passthru
     vm::bhyve_device_fbuf
     vm::bhyve_device_mouse
+    vm::bhyve_device_sound
     vm::bhyve_device_console
 
     vm::lock
@@ -718,6 +719,16 @@ vm::bhyve_device_mouse(){
     fi
 }
 
+vm::bhyve_device_sound(){
+    local _play
+    config::get "_play" "sound_play" "/dev/dsp0"
+
+    if config::yesno "sound"; then
+        _devices="${_devices} -s ${_slot}:0,hda,play=${_play}"
+        _slot=$((_slot + 1))
+    fi
+}
+
 # add virtio_console devices to the guest
 #
 # @modifies _devices _slot