ASoC: stm32: i2s: manage error when getting reset controller

Return an error when the i2s driver fails to get a reset controller.
Also add an error trace, except on probe defer status.
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20200203100814.22944-4-olivier.moysan@st.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_i2s.c

@@ -866,12 +866,16 @@ static int stm32_i2s_parse_dt(struct platform_device *pdev,
 	}
 
 	/* Reset */
-	rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
-	if (!IS_ERR(rst)) {
-		reset_control_assert(rst);
-		udelay(2);
-		reset_control_deassert(rst);
+	rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(rst)) {
+		if (PTR_ERR(rst) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Reset controller error %ld\n",
+				PTR_ERR(rst));
+		return PTR_ERR(rst);
 	}
+	reset_control_assert(rst);
+	udelay(2);
+	reset_control_deassert(rst);
 
 	return 0;
 }