remoteproc: stm32: Fix error code in stm32_rproc_parse_dt()

There is a cut and paste bug so this code was returning the wrong
variable.  It should have been "ddata->hold_boot_rst" instead of
"ddata->rst".

Fixes: de59869 ("remoteproc: stm32: Allow hold boot management by the SCMI reset controller")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/6f457246-6446-42cb-81ae-d37221d726b1@kili.mountain
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: Dan Carpenter

drivers/remoteproc/stm32_rproc.c

@@ -755,7 +755,7 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev,
 
 	ddata->hold_boot_rst = devm_reset_control_get_optional(dev, "hold_boot");
 	if (IS_ERR(ddata->hold_boot_rst))
-		return dev_err_probe(dev, PTR_ERR(ddata->rst),
+		return dev_err_probe(dev, PTR_ERR(ddata->hold_boot_rst),
 				     "failed to get hold_boot reset\n");
 
 	if (!ddata->hold_boot_rst && IS_ENABLED(CONFIG_HAVE_ARM_SMCCC)) {