[ALSA] Fix compilation without CONFIG_PROC_FS

Memalloc module
Fix an error when built without CONFIG_PROC_FS.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/memalloc.c

@@ -655,7 +655,6 @@ static int __init snd_mem_init(void)
 
 static void __exit snd_mem_exit(void)
 {
-	if (snd_mem_proc)
 	remove_proc_entry(SND_MEM_PROC_FILE, NULL);
 	free_all_reserved_pages();
 	if (snd_allocated_pages > 0)