RDMA/rxe: Fixup rxe_send and rxe_loopback

Fixup rxe_send() and rxe_loopback() in rxe_net.c to have the same calling
sequence. This patch makes them static and have the same parameter list
and return value.

Link: https://lore.kernel.org/r/20210707040040.15434-4-rpearsonhpe@gmail.com


Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>