USB: ehci-platform: fix companion-device leak

Make sure do drop the reference taken to the companion device during
resume.

Fixes: d4d75128b8 ("usb: host: ehci-platform: fix usb 1.1 device is not connected in system resume")
Cc: stable <stable@vger.kernel.org>     # 4.11
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-platform.c

@@ -384,8 +384,10 @@ static int ehci_platform_resume(struct device *dev)
 	}
 
 	companion_dev = usb_of_get_companion_dev(hcd->self.controller);
-	if (companion_dev)
+	if (companion_dev) {
 		device_pm_wait_for_dev(hcd->self.controller, companion_dev);
+		put_device(companion_dev);
+	}
 
 	ehci_resume(hcd, priv->reset_on_resume);
 	return 0;