[ALSA] add struct snd_pcm_substream forward declaration

fixes: include/sound/pcm.h:62: warning: 'struct snd_pcm_substream' declared
inside parameter list

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index ec006ed8cd59..ee6bc2d06803 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -56,6 +56,8 @@ struct snd_pcm_hardware {
         size_t fifo_size;               /* fifo size in bytes */
 };
 
+struct snd_pcm_substream;
+
 struct snd_pcm_ops {
         int (*open)(struct snd_pcm_substream *substream);
         int (*close)(struct snd_pcm_substream *substream);