misc: fastrpc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/d138bc7f6ec39038d2b5a23478fc036a41988bde.1708508896.git.u.kleine-koenig@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/fastrpc.c

@@ -2183,7 +2183,7 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int fastrpc_cb_remove(struct platform_device *pdev)
+static void fastrpc_cb_remove(struct platform_device *pdev)
 {
 	struct fastrpc_channel_ctx *cctx = dev_get_drvdata(pdev->dev.parent);
 	struct fastrpc_session_ctx *sess = dev_get_drvdata(&pdev->dev);
@@ -2198,8 +2198,6 @@ static int fastrpc_cb_remove(struct platform_device *pdev)
 		}
 	}
 	spin_unlock_irqrestore(&cctx->lock, flags);
-
-	return 0;
 }
 
 static const struct of_device_id fastrpc_match_table[] = {
@@ -2209,7 +2207,7 @@ static const struct of_device_id fastrpc_match_table[] = {
 
 static struct platform_driver fastrpc_cb_driver = {
 	.probe = fastrpc_cb_probe,
-	.remove = fastrpc_cb_remove,
+	.remove_new = fastrpc_cb_remove,
 	.driver = {
 		.name = "qcom,fastrpc-cb",
 		.of_match_table = fastrpc_match_table,