ALSA: compress: update struct snd_codec_desc for sample rate

Now that we don't use SNDRV_PCM_RATE_xxx bit fields for sample rate, we need to
change the description to an array for describing the sample rates supported by
the sink/source

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>