RDMA: Convert RWQ table logic to ib_core allocation scheme

Move struct ib_rwq_ind_table allocation to ib_core.

Link: https://lore.kernel.org/r/20200902081623.746359-3-leon@kernel.org


Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>