make cdrom.c:check_for_audio_disc() static

This patch makes the needlessly global check_for_audio_disc() static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index db259e6..12f5bae 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1152,8 +1152,8 @@
 /* This code is similar to that in open_for_data. The routine is called
    whenever an audio play operation is requested.
 */
-int check_for_audio_disc(struct cdrom_device_info * cdi,
-			 struct cdrom_device_ops * cdo)
+static int check_for_audio_disc(struct cdrom_device_info * cdi,
+				struct cdrom_device_ops * cdo)
 {
         int ret;
 	tracktype tracks;