Push AUD_init down to devices

Now we can safely call AUD_init multiple times we can push it down to
individual audio devices, rather than having to pass it from the board
init.

Signed-off-by: Paul Brook <paul@codesourcery.com>
diff --git a/hw/cs4231a.c b/hw/cs4231a.c
index 25ad409..4212ed1 100644
--- a/hw/cs4231a.c
+++ b/hw/cs4231a.c
@@ -636,16 +636,12 @@
     return 0;
 }
 
-int cs4231a_init (AudioState *audio, qemu_irq *pic)
+int cs4231a_init (qemu_irq *pic)
 {
+    AudioState *audio = AUD_init();
     int i;
     CSState *s;
 
-    if (!audio) {
-        lerr ("No audio state\n");
-        return -1;
-    }
-
     s = qemu_mallocz (sizeof (*s));
 
     s->pic = pic;