staging: usbip: fix wrong endian conversion

Fix number_of_packets wrong endian conversion in function
correct_endian_ret_submit()

Signed-off-by: David Chang <dchang@novell.com>
Acked-by: Arjan Mels <arjan.mels@gmx.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>