ALSA: ice1712: Use the standard snd_ctl_add_followers() helper

ALSA: ice1712: Use the standard snd_ctl_add_followers() helper

Instead of open-code, use the new standard helper to manage vmaster
stuff for code simplification.

Also, handle the errors from the helper more properly instead of
silently ignoring.

The code changes the call order of snd_ctl_add() of the vmaster object
and its followers for avoiding the possible memory leaks at error
path.  But there should be no difference in the functionality.

Link: https://lore.kernel.org/r/20230721071643.3631-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>