MX31: add delay between USB port setup and reset

Sometimes a usb tree is not popolated after a system reset.
It seems a delay is required after setting the USB ports
for the MX.31 before resetting the ehci controller.
Signed-off-by: NStefano Babic <sbabic@denx.de>

drivers/usb/host/ehci-mxc.c

@@ -117,6 +117,8 @@ int ehci_hcd_init(void)
 
 	mxc_set_usbcontrol(CONFIG_MXC_USB_PORT, CONFIG_MXC_USB_FLAGS);
 
+	udelay(10000);
+
 	return 0;
 }