RDMA/bnxt_re: Refactor code around bnxt_qplib_map_rc()

Update function comment of bnxt_qplib_map_rc()

Remove intermediate return value ENXIO and directly called
bnxt_qplib_map_rc() from __send_message_basic_sanity().

Link: https://lore.kernel.org/r/20230616061700.741769-2-kashyap.desai@broadcom.com
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>