usb: ehci: Do not de-init uninited controllers

In case the controller is not initialized, we shall not de-initialize it.
As the control structure will not be filled, we will produce a null ptr
dereference if the controller is not inited.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Simon Glass <sjg@chromium.org>

drivers/usb/host/ehci-hcd.c

@@ -201,6 +201,9 @@ static int ehci_shutdown(struct ehci_ctrl *ctrl)
 	int i, ret = 0;
 	uint32_t cmd, reg;
 
+	if (!ctrl || !ctrl->hcor)
+		return -EINVAL;
+
 	cmd = ehci_readl(&ctrl->hcor->or_usbcmd);
 	cmd &= ~(CMD_PSE | CMD_ASE);
 	ehci_writel(&ctrl->hcor->or_usbcmd, cmd);