Fixes gcc '-Wunused-but-set-variable' warning:
sound/soc/stm/stm32_sai_sub.c: In function 'stm32_sai_configure_clock':
sound/soc/stm/stm32_sai_sub.c:902:11: warning:
 variable 'mask' set but not used [-Wunused-but-set-variable]
sound/soc/stm/stm32_sai_sub.c:902:6: warning:
 variable 'cr1' set but not used [-Wunused-but-set-variable]
It's not used any more after 
8307b2afd386 ("ASoC: stm32: sai: set sai as
mclk clock provider")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
 
                                     struct snd_pcm_hw_params *params)
 {
        struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
-       int cr1, mask, div = 0;
+       int div = 0;
        int sai_clk_rate, mclk_ratio, den;
        unsigned int rate = params_rate(params);
 
                } else {
                        if (sai->mclk_rate) {
                                mclk_ratio = sai->mclk_rate / rate;
-                               if (mclk_ratio == 512) {
-                                       mask = SAI_XCR1_OSR;
-                                       cr1 = SAI_XCR1_OSR;
-                               } else if (mclk_ratio != 256) {
+                               if ((mclk_ratio != 512) &&
+                                   (mclk_ratio != 256)) {
                                        dev_err(cpu_dai->dev,
                                                "Wrong mclk ratio %d\n",
                                                mclk_ratio);