USB: rename USB_SPEED_VARIABLE to USB_SPEED_WIRELESS

It's really the wireless speed, so rename the thing to make
more sense.  Based on a recommendation from David Vrabel

Cc: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index e2bd153..2708056 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -437,7 +437,7 @@
 	case USB_ENDPOINT_XFER_INT:
 		/* too small? */
 		switch (dev->speed) {
-		case USB_SPEED_VARIABLE:
+		case USB_SPEED_WIRELESS:
 			if (urb->interval < 6)
 				return -EINVAL;
 			break;
@@ -453,7 +453,7 @@
 			if (urb->interval > (1 << 15))
 				return -EINVAL;
 			max = 1 << 15;
-		case USB_SPEED_VARIABLE:
+		case USB_SPEED_WIRELESS:
 			if (urb->interval > 16)
 				return -EINVAL;
 			break;
@@ -480,7 +480,7 @@
 		default:
 			return -EINVAL;
 		}
-		if (dev->speed != USB_SPEED_VARIABLE) {
+		if (dev->speed != USB_SPEED_WIRELESS) {
 			/* Round down to a power of 2, no more than max */
 			urb->interval = min(max, 1 << ilog2(urb->interval));
 		}