staging: ozwpan: fix access byteorder for wMaxPacketSize in ozhcd.c

This patch fixes the access byteorder of wMaxPacketSize
which is __le16, following the USB standard, and needs to
be converted into native cpu byteorder in order to be accessed.

Instead of using le16_to_cpu(hep->desc.wMaxPacketSize),
it was used the usb_endpoint_maxp() function, defined in
<uapi/linux/usb/ch9.h>

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>