USB: SS: Add support for Super Speed USB interface

This adds usb framework support for super-speed usb, which will
further facilitate to add stack support for xHCI.

Signed-off-by: Vikas C Sajjan <vikas.sajjan@samsung.com>
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
diff --git a/common/cmd_usb.c b/common/cmd_usb.c
index adc5f02..70e803b 100644
--- a/common/cmd_usb.c
+++ b/common/cmd_usb.c
@@ -287,12 +287,24 @@
 
 static inline char *portspeed(int speed)
 {
-	if (speed == USB_SPEED_HIGH)
-		return "480 Mb/s";
-	else if (speed == USB_SPEED_LOW)
-		return "1.5 Mb/s";
-	else
-		return "12 Mb/s";
+	char *speed_str;
+
+	switch (speed) {
+	case USB_SPEED_SUPER:
+		speed_str = "5 Gb/s";
+		break;
+	case USB_SPEED_HIGH:
+		speed_str = "480 Mb/s";
+		break;
+	case USB_SPEED_LOW:
+		speed_str = "1.5 Mb/s";
+		break;
+	default:
+		speed_str = "12 Mb/s";
+		break;
+	}
+
+	return speed_str;
 }
 
 /* shows the device tree recursively */