remoteproc: stm32: improve debug using dev_err_probe

When possible use dev_err_probe help to properly deal with the
PROBE_DEFER error.
The benefit is that DEFER issue will be logged in the devices_deferred
debugfs file.
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss-st.com>
Link: https://lore.kernel.org/r/20201217144125.12903-1-arnaud.pouliquen@foss.st.comSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/stm32_rproc.c

@@ -370,8 +370,13 @@ static int stm32_rproc_request_mbox(struct rproc *rproc)
 
 		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
 		if (IS_ERR(ddata->mb[i].chan)) {
-			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER)
+			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER) {
+				dev_err_probe(dev->parent,
+					      PTR_ERR(ddata->mb[i].chan),
+					      "failed to request mailbox %s\n",
+					      name);
 				goto err_probe;
+			}
 			dev_warn(dev, "cannot get %s mbox\n", name);
 			ddata->mb[i].chan = NULL;
 		}
@@ -592,15 +597,14 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev,
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq == -EPROBE_DEFER)
-		return -EPROBE_DEFER;
+		return dev_err_probe(dev, irq, "failed to get interrupt\n");
 
 	if (irq > 0) {
 		err = devm_request_irq(dev, irq, stm32_rproc_wdg, 0,
 				       dev_name(dev), pdev);
-		if (err) {
-			dev_err(dev, "failed to request wdg irq\n");
-			return err;
-		}
+		if (err)
+			return dev_err_probe(dev, err,
+					     "failed to request wdg irq\n");
 
 		ddata->wdg_irq = irq;
 
@@ -613,10 +617,9 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev,
 	}
 
 	ddata->rst = devm_reset_control_get_by_index(dev, 0);
-	if (IS_ERR(ddata->rst)) {
-		dev_err(dev, "failed to get mcu reset\n");
-		return PTR_ERR(ddata->rst);
-	}
+	if (IS_ERR(ddata->rst))
+		return dev_err_probe(dev, PTR_ERR(ddata->rst),
+				     "failed to get mcu_reset\n");
 
 	/*
 	 * if platform is secured the hold boot bit must be written by