ALSA: usb: Remove superfluous snd_pcm_suspend*() calls

The call of snd_pcm_suspend_all() & co became superfluous since we
call it in the PCM PM ops.  Let's remove them.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>