RDMA/bnxt_re: Handle variable WQE support for user applications

RDMA/bnxt_re: Handle variable WQE support for user applications

User library calculates the number of slots required for user applications
and it can pass that information to the driver.  Driver can use this value
and update the HW directly. This mechanism is currently used only for the
newly introduced variable size WQEs.

Extend the bnxt_re_qp_req structure to pass the Send Queue slot count.
Reorganize the code to get the sq_slots before initializing the Send Queue
attributes.

Link: https://patch.msgid.link/r/1724042847-1481-5-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Hongguang Gao <hongguang.gao@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>