USB: xhci: Set Mult field in endpoint context correctly.

The bmAttributes field of the SuperSpeed Endpoint Companion Descriptor has
different meanings, depending on the endpoint type.  If the endpoint is
isochronous, the bmAttributes field is the maximum number of packets
within a service interval that this endpoint supports.  If the endpoint is
bulk, it's the number of stream IDs this endpoint supports.

Only set the Mult field of the xHCI endpoint context using the
bmAttributes field if the endpoint is isochronous, and the device is a
SuperSpeed device.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci-mem.c

@@ -1023,7 +1023,7 @@ static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
 	return EP_INTERVAL(interval);
 }
 
-/* The "Mult" field in the endpoint context is only set for SuperSpeed devices.
+/* The "Mult" field in the endpoint context is only set for SuperSpeed isoc eps.
  * High speed endpoint descriptors can define "the number of additional
  * transaction opportunities per microframe", but that goes in the Max Burst
  * endpoint context field.
@@ -1031,7 +1031,8 @@ static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
 static inline u32 xhci_get_endpoint_mult(struct usb_device *udev,
 		struct usb_host_endpoint *ep)
 {
-	if (udev->speed != USB_SPEED_SUPER)
+	if (udev->speed != USB_SPEED_SUPER ||
+			!usb_endpoint_xfer_isoc(&ep->desc))
 		return 0;
 	return ep->ss_ep_comp.bmAttributes;
 }