ALSA: oss: don't opencode IS_REACHABLE()

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/pcm_oss.c

@@ -2501,7 +2501,7 @@ static long snd_pcm_oss_ioctl(struct file *file, unsigned int cmd, unsigned long
 		return put_user(SNDRV_OSS_VERSION, p);
 	if (cmd == OSS_ALSAEMULVER)
 		return put_user(1, p);
-#if defined(CONFIG_SND_MIXER_OSS) || (defined(MODULE) && defined(CONFIG_SND_MIXER_OSS_MODULE))
+#if IS_REACHABLE(CONFIG_SND_MIXER_OSS)
 	if (((cmd >> 8) & 0xff) == 'M')	{	/* mixer ioctl - for OSS compatibility */
 		struct snd_pcm_substream *substream;
 		int idx;