remoteproc: qcom: Add shutdown-ack irq

Add shutdown-ack irq handling required for sysmon shutdown for
Q6V5 MSS on SDM845/MSM8996 and for WCSS Q6V5 on QCS404 SoC.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
[bjorn: Revert back to qcom_add_sysmon_subdev returning a sysmon object]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c
index b1e63fc..c529a04 100644
--- a/drivers/remoteproc/qcom_q6v5_pas.c
+++ b/drivers/remoteproc/qcom_q6v5_pas.c
@@ -304,6 +304,10 @@ static int adsp_probe(struct platform_device *pdev)
 	adsp->sysmon = qcom_add_sysmon_subdev(rproc,
 					      desc->sysmon_name,
 					      desc->ssctl_id);
+	if (IS_ERR(adsp->sysmon)) {
+		ret = PTR_ERR(adsp->sysmon);
+		goto free_rproc;
+	}
 
 	ret = rproc_add(rproc);
 	if (ret)