ASoC: stm32: sai: fix noderef.cocci warnings

sound/soc/stm/stm32_sai_sub.c:393:26-32: ERROR: application of sizeof to pointer

 sizeof when applied to a pointer typed expression gives the size of
 the pointer

Generated by: scripts/coccinelle/misc/noderef.cocci

Fixes: 8307b2afd386 ("ASoC: stm32: sai: set sai as mclk clock provider")
CC: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_sai_sub.c

@@ -390,7 +390,7 @@ static int stm32_sai_add_mclk_provider(struct stm32_sai_sub_data *sai)
 	char *mclk_name, *p, *s = (char *)pname;
 	int ret, i = 0;
 
-	mclk = devm_kzalloc(dev, sizeof(mclk), GFP_KERNEL);
+	mclk = devm_kzalloc(dev, sizeof(*mclk), GFP_KERNEL);
 	if (!mclk)
 		return -ENOMEM;