mailbox: qcom-apcs: Use device-managed registration API

Get rid of some boilerplate driver removal code by using the newly added
device-managed registration API.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/qcom-apcs-ipc-mailbox.c

@@ -91,7 +91,7 @@ static int qcom_apcs_ipc_probe(struct platform_device *pdev)
 	apcs->mbox.chans = apcs->mbox_chans;
 	apcs->mbox.num_chans = ARRAY_SIZE(apcs->mbox_chans);
 
-	ret = mbox_controller_register(&apcs->mbox);
+	ret = devm_mbox_controller_register(&pdev->dev, &apcs->mbox);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register APCS IPC controller\n");
 		return ret;
@@ -115,7 +115,6 @@ static int qcom_apcs_ipc_remove(struct platform_device *pdev)
 	struct qcom_apcs_ipc *apcs = platform_get_drvdata(pdev);
 	struct platform_device *clk = apcs->clk;
 
-	mbox_controller_unregister(&apcs->mbox);
 	platform_device_unregister(clk);
 
 	return 0;