ALSA: cs46xx: Fix suspend for all channels

snd_cs46xx_suspend() is missing snd_pcm_suspend_all calls for pcm_rear,
pcm_center_lfe and pcm_iec958.

There's also a copy/paste bug in snd_cs46xx_pcm_iec958(), overwriting
pcm_rear in struct snd_cs46xx, leaving pcm_iec958 unused.

Fix all this to allow all channels to survive suspend/resume.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>