remoteproc: stm32: Clean up redundant dev_err_probe()

Referring to platform_get_irq()'s definition, the return value has
already been checked if ret < 0, and printed via dev_err_probe().
Calling dev_err_probe() one more time outside platform_get_irq()
is obviously redundant. Removing outside dev_err_probe() to
clean it up.

Besides, switch to use platform_get_irq_optional() since the irq
is optional here.
Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20230817083336.404635-1-chenjiahao16@huawei.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/remoteproc/stm32_rproc.c

@@ -712,9 +712,9 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev,
 	unsigned int tzen;
 	int err, irq;
 
-	irq = platform_get_irq(pdev, 0);
+	irq = platform_get_irq_optional(pdev, 0);
 	if (irq == -EPROBE_DEFER)
-		return dev_err_probe(dev, irq, "failed to get interrupt\n");
+		return irq;
 
 	if (irq > 0) {
 		err = devm_request_irq(dev, irq, stm32_rproc_wdg, 0,