net: wireless: orinoco: orinoco_usb.c: fix DMA buffers on stack

This patch fixes an instance of DMA buffer on stack(being passed to
usb_control_msg) for the wireless USB version of the Agere Orinoco card driver.
It also fixes the missing audit for the return value of firmware download
routine. Found using smatch.

Signed-off-by: Kumar Amit Mehta <gmate.amit@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>