drivers/usb/wusbcore/wa-hc.c: fix error return code

Convert a 0 error return code to a negative one, as returned elsewhere in the
function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret;
expression e,e1,e2,e3,e4,x;
@@

(
if (\(ret != 0\|ret < 0\) || ...) { ... return ...; }
|
ret = 0
)
... when != ret = e1
*x = \(kmalloc\|kzalloc\|kcalloc\|devm_kzalloc\|ioremap\|ioremap_nocache\|devm_ioremap\|devm_ioremap_nocache\)(...);
... when != x = e2
    when != ret = e3
*if (x == NULL || ...)
{
  ... when != ret = e4
*  return ret;
}
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/wusbcore/wa-hc.c

@@ -46,8 +46,10 @@ int wa_create(struct wahc *wa, struct usb_interface *iface)
 	wa->dto_epd = &iface->cur_altsetting->endpoint[2].desc;
 	wa->xfer_result_size = usb_endpoint_maxp(wa->dti_epd);
 	wa->xfer_result = kmalloc(wa->xfer_result_size, GFP_KERNEL);
-	if (wa->xfer_result == NULL)
+	if (wa->xfer_result == NULL) {
+		result = -ENOMEM;
 		goto error_xfer_result_alloc;
+	}
 	result = wa_nep_create(wa, iface);
 	if (result < 0) {
 		dev_err(dev, "WA-CDS: can't initialize notif endpoint: %d\n",