ALSA: pcm: fix the comments that refers to kernel-doc

The markup inside the #if 0 comment actually refers to a
kernel-doc markup. As we're getting rid of DocBook update it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/pcm.h

@@ -1055,7 +1055,7 @@ int snd_pcm_format_unsigned(snd_pcm_format_t format);
 int snd_pcm_format_linear(snd_pcm_format_t format);
 int snd_pcm_format_little_endian(snd_pcm_format_t format);
 int snd_pcm_format_big_endian(snd_pcm_format_t format);
-#if 0 /* just for DocBook */
+#if 0 /* just for kernel-doc */
 /**
  * snd_pcm_format_cpu_endian - Check the PCM format is CPU-endian
  * @format: the format to check