ALSA: usb-audio: UAC2: do clock validity check earlier

Move the check that parse_audio_format_rates_v2() do after
receiving the clock source entity ID directly into the find
function and add a validation flag to the function.

This patch does not introduce any logic flow change.

It is provided to allow introducing automatic clock switching
easier later. By moving this uac_clock_source_is_valid callsite,
2 additional callsites can be avoided.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/clock.h b/sound/usb/clock.h
index 4663093..d592e4a 100644
--- a/sound/usb/clock.h
+++ b/sound/usb/clock.h
@@ -5,6 +5,7 @@
 			     struct usb_host_interface *alts,
 			     struct audioformat *fmt, int rate);
 
-int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id);
+int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
+			     bool validate);
 
 #endif /* __USBAUDIO_CLOCK_H */