ASoC: stm32: i2s: fix 32 bits channel length without mclk

Fix divider calculation in the case of 32 bits channel
configuration, when no master clock is used.

Fixes: e4e6ec7b ("ASoC: stm32: Add I2S driver")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Link: https://lore.kernel.org/r/20211117104404.3832-1-olivier.moysan@foss.st.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_i2s.c

@@ -700,7 +700,7 @@ static int stm32_i2s_configure_clock(struct snd_soc_dai *cpu_dai,
 		if (ret < 0)
 			return ret;
 
-		nb_bits = frame_len * ((cgfr & I2S_CGFR_CHLEN) + 1);
+		nb_bits = frame_len * (FIELD_GET(I2S_CGFR_CHLEN, cgfr) + 1);
 		ret = stm32_i2s_calc_clk_div(i2s, i2s_clock_rate,
 					     (nb_bits * rate));
 		if (ret)