MADI and MADIface used to report the autosync_sample_rate. This
functionality was lost in commit 0dca1793063c28dde8f6c49c9c72203fe5cb6efc, this commit now adds it back.
Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>