RDMA/bnxt_en: Enable RDMA driver support for 57500 chip

Re-enabling RDMA driver support on 57500 chips. Removing the forced error
code for 57500 chip.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>