orinoco_usb: Fix broken firmware load error checking

The check of ezusb_firmware_download() return value (added by commit
488ec878) is broken because
ezusb_firmware_download() returns 1 on success.
This causes the driver not to work with the following error:
orinoco_usb: probe of 3-3:1.0 failed with error -14

Check the return value only for negative values.

This fix should be applied to -stable kernels too.
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/orinoco/orinoco_usb.c

@@ -1687,7 +1687,7 @@ static int ezusb_probe(struct usb_interface *interface,
 		firmware.code = fw_entry->data;
 	}
 	if (firmware.size && firmware.code) {
-		if (ezusb_firmware_download(upriv, &firmware))
+		if (ezusb_firmware_download(upriv, &firmware) < 0)
 			goto error;
 	} else {
 		err("No firmware to download");