RDMA/i40iw: Move uapi header to include/uapi

All of these defines are part of the uABI for the driver, this
header duplicates providers/i40iw/i40iw-abi.h in rdma-core.

Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>