usb: dwc3: of-simple: add a shutdown

In case we're loading a new kernel via kexec, let's make sure to
cleanup the dwc3 address space correctly. This means that we should
run the same steps from driver remove, so just extract a reusable
function for both cases.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/dwc3-of-simple.c

@@ -110,12 +110,9 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int dwc3_of_simple_remove(struct platform_device *pdev)
+static void __dwc3_of_simple_teardown(struct dwc3_of_simple *simple)
 {
-	struct dwc3_of_simple	*simple = platform_get_drvdata(pdev);
-	struct device		*dev = &pdev->dev;
-
-	of_platform_depopulate(dev);
+	of_platform_depopulate(simple->dev);
 
 	clk_bulk_disable_unprepare(simple->num_clocks, simple->clks);
 	clk_bulk_put_all(simple->num_clocks, simple->clks);
@@ -126,13 +123,27 @@ static int dwc3_of_simple_remove(struct platform_device *pdev)
 
 	reset_control_put(simple->resets);
 
-	pm_runtime_disable(dev);
-	pm_runtime_put_noidle(dev);
-	pm_runtime_set_suspended(dev);
+	pm_runtime_disable(simple->dev);
+	pm_runtime_put_noidle(simple->dev);
+	pm_runtime_set_suspended(simple->dev);
+}
+
+static int dwc3_of_simple_remove(struct platform_device *pdev)
+{
+	struct dwc3_of_simple	*simple = platform_get_drvdata(pdev);
+
+	__dwc3_of_simple_teardown(simple);
 
 	return 0;
 }
 
+static void dwc3_of_simple_shutdown(struct platform_device *pdev)
+{
+	struct dwc3_of_simple	*simple = platform_get_drvdata(pdev);
+
+	__dwc3_of_simple_teardown(simple);
+}
+
 static int __maybe_unused dwc3_of_simple_runtime_suspend(struct device *dev)
 {
 	struct dwc3_of_simple	*simple = dev_get_drvdata(dev);
@@ -190,6 +201,7 @@ MODULE_DEVICE_TABLE(of, of_dwc3_simple_match);
 static struct platform_driver dwc3_of_simple_driver = {
 	.probe		= dwc3_of_simple_probe,
 	.remove		= dwc3_of_simple_remove,
+	.shutdown	= dwc3_of_simple_shutdown,
 	.driver		= {
 		.name	= "dwc3-of-simple",
 		.of_match_table = of_dwc3_simple_match,