ALSA: wss-lib: remove "pops" before each played sound

A WSS codec is autocalibrated each time before
playing sound. Do only one calibration during
codec initialization.

Complete snd_wss_calibrate_mute to mute loopback
volume as well.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>