USB: remove 8 bytes of padding from usb_host_interface on 64 bit builds

Reorder elements in the usb_host_interface structure to remove 8 bytes
of padding on 64 bit builds , and so shrink it's size to 40 bytes.

usb_interface_descriptor is a odd size which leaves a gap that is not
big enough to hold a pointer, so moving extralen into that gap removes
the need for more padding.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/usb.h

@@ -77,14 +77,15 @@ struct usb_host_endpoint {
 struct usb_host_interface {
 	struct usb_interface_descriptor	desc;
 
+	int extralen;
+	unsigned char *extra;   /* Extra descriptors */
+
 	/* array of desc.bNumEndpoint endpoints associated with this
 	 * interface setting.  these will be in no particular order.
 	 */
 	struct usb_host_endpoint *endpoint;
 
 	char *string;		/* iInterface string, if present */
-	unsigned char *extra;   /* Extra descriptors */
-	int extralen;
 };
 
 enum usb_interface_condition {