usb: return correct errno on failures

In function __wa_xfer_setup_segs(), variable result takes the return
value. Its value should be a negative errno on failures. Because result
may be reassigned in a loop, and its value is guaranteed to be not less
than 0 during the following repeats of the loop. So when the call to
kmalloc() or usb_alloc_urb() fails in the loop, the value of variable
result may be 0 (indicates no error), which is inconsistent with the
execution status. This patch fixes the bug, initializing variable result
with -ENOMEM in the loop.
Signed-off-by: NPan Bian <bianpan2016@163.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/wusbcore/wa-xfer.c

@@ -1203,6 +1203,7 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
 				sizeof(struct wa_xfer_packet_info_hwaiso) +
 				(seg_isoc_frame_count * sizeof(__le16));
 		}
+		result = -ENOMEM;
 		seg = xfer->seg[cnt] = kmalloc(alloc_size + iso_pkt_descr_size,
 						GFP_ATOMIC);
 		if (seg == NULL)