RDMA/i40iw: Fix endian issues and warnings

Fix endian warnings and errors due to u32 stored to u16.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>