staging: bcm2835-audio: Make internal symbols static

Fixes sparse warnings:
warning: symbol 'xxx' was not declared. Should it be static?
Signed-off-by: Simon Sandström <simon@nikanor.nu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/bcm2835-audio/bcm2835-vchiq.c

@@ -195,13 +195,13 @@ int bcm2835_audio_write(struct bcm2835_alsa_stream *alsa_stream,
 	return ret;
 }
 
-void my_workqueue_init(struct bcm2835_alsa_stream *alsa_stream)
+static void my_workqueue_init(struct bcm2835_alsa_stream *alsa_stream)
 {
 	alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
 	return;
 }
 
-void my_workqueue_quit(struct bcm2835_alsa_stream *alsa_stream)
+static void my_workqueue_quit(struct bcm2835_alsa_stream *alsa_stream)
 {
 	if (alsa_stream->my_wq) {
 		flush_workqueue(alsa_stream->my_wq);
@@ -782,7 +782,7 @@ int bcm2835_audio_close(struct bcm2835_alsa_stream *alsa_stream)
 	return ret;
 }
 
-int bcm2835_audio_write_worker(struct bcm2835_alsa_stream *alsa_stream,
+static int bcm2835_audio_write_worker(struct bcm2835_alsa_stream *alsa_stream,
 				      unsigned int count, void *src)
 {
 	struct vc_audio_msg m;