usb: cmd: Print actual packet size for super speed devices

USB 3.0 defines bMaxPacketSize0 field in the device descriptor as
the exponent of 2, so let's print the calculated actual size.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Stefan Roese <sr@denx.de>

cmd/usb.c

@@ -150,6 +150,8 @@ static void usb_display_string(struct usb_device *dev, int index)
 
 static void usb_display_desc(struct usb_device *dev)
 {
+	uint packet_size = dev->descriptor.bMaxPacketSize0;
+
 	if (dev->descriptor.bDescriptorType == USB_DT_DEVICE) {
 		printf("%d: %s,  USB Revision %x.%x\n", dev->devnum,
 		usb_get_class_desc(dev->config.if_desc[0].desc.bInterfaceClass),
@@ -171,9 +173,10 @@ static void usb_display_desc(struct usb_device *dev)
 			       usb_get_class_desc(
 				dev->config.if_desc[0].desc.bInterfaceClass));
 		}
+		if (dev->descriptor.bcdUSB >= cpu_to_le16(0x0300))
+			packet_size = 1 << packet_size;
 		printf(" - PacketSize: %d  Configurations: %d\n",
-			dev->descriptor.bMaxPacketSize0,
-			dev->descriptor.bNumConfigurations);
+			packet_size, dev->descriptor.bNumConfigurations);
 		printf(" - Vendor: 0x%04x  Product 0x%04x Version %d.%d\n",
 			dev->descriptor.idVendor, dev->descriptor.idProduct,
 			(dev->descriptor.bcdDevice>>8) & 0xff,