[ALSA] Remove zero-initialization of static variables

Removed zero-initializations of static variables.
A tiny optimization.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index bc00f9b..7581edd 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -1072,7 +1072,7 @@
 	mutex_unlock(&register_mutex);
 }
 
-static struct snd_info_entry *snd_pcm_proc_entry = NULL;
+static struct snd_info_entry *snd_pcm_proc_entry;
 
 static void snd_pcm_proc_init(void)
 {