ALSA: compress: add num_sample_rates in snd_codec_desc

this gives ability to convey the valid values of supported rates in
sample_rates array

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

include/uapi/sound/compress_params.h

@@ -326,6 +326,7 @@ union snd_codec_options {
 /** struct snd_codec_desc - description of codec capabilities
  * @max_ch: Maximum number of audio channels
  * @sample_rates: Sampling rates in Hz, use values like 48000 for this
+ * @num_sample_rates: Number of valid values in sample_rates array
  * @bit_rate: Indexed array containing supported bit rates
  * @num_bitrates: Number of valid values in bit_rate array
  * @rate_control: value is specified by SND_RATECONTROLMODE defines.
@@ -348,6 +349,7 @@ union snd_codec_options {
 struct snd_codec_desc {
 	__u32 max_ch;
 	__u32 sample_rates[MAX_NUM_SAMPLE_RATES];
+	__u32 num_sample_rates;
 	__u32 bit_rate[MAX_NUM_BITRATES];
 	__u32 num_bitrates;
 	__u32 rate_control;