ASoC: wm8903: remove useless assignments

cppcheck warnings:

sound/soc/codecs/wm8903.c:1552:11: style: Variable 'best_val' is
assigned a value that is never used. [unreadVariable]
 best_val = ((clk_sys * 10) / bclk_divs[0].ratio) - bclk;
          ^
sound/soc/codecs/wm8903.c:1559:12: style: Variable 'best_val' is
assigned a value that is never used. [unreadVariable]
  best_val = cur_val;
           ^

Indeed what matters in the code is the blck_div, the best_val is
assigned but never tested or used.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210311004332.120901-5-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8903.c

@@ -1549,14 +1549,12 @@ static int wm8903_hw_params(struct snd_pcm_substream *substream,
 	 * BCLKs to clock out the samples).
 	 */
 	bclk_div = 0;
-	best_val = ((clk_sys * 10) / bclk_divs[0].ratio) - bclk;
 	i = 1;
 	while (i < ARRAY_SIZE(bclk_divs)) {
 		cur_val = ((clk_sys * 10) / bclk_divs[i].ratio) - bclk;
 		if (cur_val < 0) /* BCLK table is sorted */
 			break;
 		bclk_div = i;
-		best_val = cur_val;
 		i++;
 	}