RDMA/rxe: Cleanup init_send_wqe

This patch changes the type of init_send_wqe in rxe_verbs.c to void since
it always returns 0. It also separates out the code that copies inline
data into the send wqe as copy_inline_data_to_wqe().

Link: https://lore.kernel.org/r/20210206002437.2756-1-rpearson@hpe.com


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