ALSA: HDA: Add access description in __snd_hda_add_vmaster

ALSA: HDA: Add access description in __snd_hda_add_vmaster

Add description for access parameter in __snd_hda_add_vmaster()
to prevent the compilation warning:
warning: Function parameter or member 'access' not described in '__snd_hda_add_vmaster'

Fixes: e65bf99718b5 ("ALSA: HDA - remove the custom implementation for the audio LED trigger")
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20210409214616.1539685-1-ranjani.sridharan@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>