soc: apple: mailbox: fix device leak on lookup

commit f401671 upstream.

Make sure to drop the reference taken to the mbox platform device when
looking up its driver data.

Note that holding a reference to a device does not prevent its driver
data from going away so there is no point in keeping the reference.

Fixes: 6e1457f ("soc: apple: mailbox: Add ASC/M3 mailbox driver")
Cc: stable@vger.kernel.org	# 6.8
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sven Peter <sven@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jhovold

drivers/soc/apple/mailbox.c

@@ -302,11 +302,18 @@ struct apple_mbox *apple_mbox_get(struct device *dev, int index)
 		return ERR_PTR(-EPROBE_DEFER);
 
 	mbox = platform_get_drvdata(pdev);
-	if (!mbox)
-		return ERR_PTR(-EPROBE_DEFER);
+	if (!mbox) {
+		mbox = ERR_PTR(-EPROBE_DEFER);
+		goto out_put_pdev;
+	}
+
+	if (!device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER)) {
+		mbox = ERR_PTR(-ENODEV);
+		goto out_put_pdev;
+	}
 
-	if (!device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_CONSUMER))
-		return ERR_PTR(-ENODEV);
+out_put_pdev:
+	put_device(&pdev->dev);
 
 	return mbox;
 }