ASoC: arizona: Suppress reference calculations when setting REFCLK to 0

Allow users to keep on specifying their output frequency when disabling
the reference clock.
Reported-by: NKyung Kwee Ryu <Kyung-Kwee.Ryu@wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/arizona.c

@@ -1249,7 +1249,7 @@ int arizona_set_fll_refclk(struct arizona_fll *fll, int source,
 	if (fll->ref_src == source && fll->ref_freq == Fref)
 		return 0;
 
-	if (fll->fout) {
+	if (fll->fout && Fref > 0) {
 		ret = arizona_calc_fll(fll, &ref, Fref, fll->fout);
 		if (ret != 0)
 			return ret;
@@ -1265,7 +1265,7 @@ int arizona_set_fll_refclk(struct arizona_fll *fll, int source,
 	fll->ref_src = source;
 	fll->ref_freq = Fref;
 
-	if (fll->fout) {
+	if (fll->fout && Fref > 0) {
 		arizona_enable_fll(fll, &ref, &sync);
 	}