RDMA/bnxt_re: Add chip context to identify 57500 series

Adding setup and destroy routines for chip-context. The chip context would
be used frequently in control and data path to take execution flow
depending on the chip type.  chip context structure pointer is added to
the relevant data structures.

Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>