ASoC: arizona: Correct relationship between VCO corner and Fref

When configuring the FLL we must ensure that the reference clock passed
to the FLL is under a certain limit. This limit was specified
incorrectly in the current code, this patch corrects this. Although the
error will only be encountered in some edge cases.
Reported-by: Ryo Tsutsui <ryo.tsutsui@wolfsonmicro.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/arizona.c

@@ -1578,8 +1578,8 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
 	while (div <= ARIZONA_FLL_MAX_REFDIV) {
 		for (ratio = init_ratio; ratio <= ARIZONA_FLL_MAX_FRATIO;
 		     ratio++) {
-			if (ARIZONA_FLL_VCO_CORNER / (fll->vco_mult * ratio) <
-			    Fref)
+			if ((ARIZONA_FLL_VCO_CORNER / 2) /
+			    (fll->vco_mult * ratio) < Fref)
 				break;
 
 			if (target % (ratio * Fref)) {