ASoC: fsl_micfil: Remove set but not used variable 'osr'

Fixes gcc '-Wunused-but-set-variable' warning:

sound/soc/fsl/fsl_micfil.c: In function 'get_clk_div':
sound/soc/fsl/fsl_micfil.c:154:6: warning: variable 'osr' set but not used [-Wunused-but-set-variable]

It is never used since introduction in
commit 47a70e6f ("ASoC: Add MICFIL SoC Digital Audio Interface driver.")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_micfil.c

@@ -151,12 +151,9 @@ static inline int get_clk_div(struct fsl_micfil *micfil,
 {
 	u32 ctrl2_reg;
 	long mclk_rate;
-	int osr;
 	int clk_div;
 
 	regmap_read(micfil->regmap, REG_MICFIL_CTRL2, &ctrl2_reg);
-	osr = 16 - ((ctrl2_reg & MICFIL_CTRL2_CICOSR_MASK)
-		    >> MICFIL_CTRL2_CICOSR_SHIFT);
 
 	mclk_rate = clk_get_rate(micfil->mclk);