ASoC: fsl_micfil: Drop unused register read

In get_pdm_clk() REG_MICFIL_CTRL2 is read, but the result is never used.
Drop the unused code.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Link: https://lore.kernel.org/r/20220414162249.3934543-3-s.hauer@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_micfil.c

@@ -148,12 +148,9 @@ static inline int get_pdm_clk(struct fsl_micfil *micfil,
 static inline int get_clk_div(struct fsl_micfil *micfil,
 			      unsigned int rate)
 {
-	u32 ctrl2_reg;
 	long mclk_rate;
 	int clk_div;
 
-	regmap_read(micfil->regmap, REG_MICFIL_CTRL2, &ctrl2_reg);
-
 	mclk_rate = clk_get_rate(micfil->mclk);
 
 	clk_div = mclk_rate / (get_pdm_clk(micfil, rate) * 2);