[ALSA] Fix Oops at rmmod with CONFIG_SND_VERBOSE_PROCFS=n

Fixed Oops at rmmod with CONFIG_SND_VERBOSE_PROCFS=n.
Add ifdef to struct fields for optimization and better compile
checks.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/pcm_oss.c

@@ -2214,7 +2214,7 @@ static int snd_pcm_oss_mmap(struct file *file, struct vm_area_struct *area)
 	return 0;
 }
 
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_SND_VERBOSE_PROCFS
 /*
  *  /proc interface
  */
@@ -2368,10 +2368,10 @@ static void snd_pcm_oss_proc_done(struct snd_pcm *pcm)
 		}
 	}
 }
-#else /* !CONFIG_PROC_FS */
+#else /* !CONFIG_SND_VERBOSE_PROCFS */
 #define snd_pcm_oss_proc_init(pcm)
 #define snd_pcm_oss_proc_done(pcm)
-#endif /* CONFIG_PROC_FS */
+#endif /* CONFIG_SND_VERBOSE_PROCFS */
 
 /*
  *  ENTRY functions