sound: Remove unnecessary casts of private_data

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 204af48..88525a9 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -364,8 +364,7 @@
 static void snd_pcm_substream_proc_info_read(struct snd_info_entry *entry,
 					     struct snd_info_buffer *buffer)
 {
-	snd_pcm_proc_info_read((struct snd_pcm_substream *)entry->private_data,
-			       buffer);
+	snd_pcm_proc_info_read(entry->private_data, buffer);
 }
 
 static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry,