coresight: etm4x: Fix merge resolution for amba rework

This was non-trivial to get right because commits
c23bc38 ("coresight: etm4x: Refactor probing routine") and
5214b56 ("coresight: etm4x: Add support for sysreg only devices")
changed the code flow considerably. With this change the driver can be
built again.

Fixes: 0573d3f ("Merge branch 'devel-stable' of git://git.armlinux.org.uk/~rmk/linux-arm into char-misc-next")
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210205130848.20009-1-uwe@kleine-koenig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etm4x-core.c

@@ -1906,15 +1906,16 @@ static int __exit etm4_remove_dev(struct etmv4_drvdata *drvdata)
 	cpus_read_unlock();
 
 	coresight_unregister(drvdata->csdev);
+
+	return 0;
 }
 
-static int __exit etm4_remove_amba(struct amba_device *adev)
+static void __exit etm4_remove_amba(struct amba_device *adev)
 {
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);
 
 	if (drvdata)
-		return etm4_remove_dev(drvdata);
-	return 0;
+		etm4_remove_dev(drvdata);
 }
 
 static int __exit etm4_remove_platform_dev(struct platform_device *pdev)