net: wwan: iosm: endianness type correction

Endianness type correction for nr_of_bytes. This field is exchanged
as part of host-device protocol communication.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>