IB/rdmavt: Rename check_send_wqe as setup_wqe

The driver-provided function check_send_wqe allows the hardware driver to
check and set up the incoming send wqe before it is inserted into the swqe
ring. This patch will rename it as setup_wqe to better reflect its
usage. In addition, this function is only called when all setup is
complete in rdmavt.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>