ALSA: pcm: Add snd_pcm_rate_bit_to_rate()

This is essentially the reverse of snd_pcm_rate_to_rate_bit().

This is generally useful as the Compress API uses the rate bit
directly and it helps to be able to map back to the actual sample
rate.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 0d11128..68372bc 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -893,6 +893,7 @@
 
 int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime);
 unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate);
+unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit);
 
 static inline void snd_pcm_set_runtime_buffer(struct snd_pcm_substream *substream,
 					      struct snd_dma_buffer *bufp)