RDMA/bnxt_re: Refactor device add/remove functionalities

 - bnxt_re_ib_reg() handles two main functionalities - initializing the
   device and registering with the IB stack.  Split it into 2 functions
   i.e. bnxt_re_dev_init() and bnxt_re_ib_init() to account for the same
   thereby improve modularity. Do the same for
   bnxt_re_ib_unreg()i.e. split into two functions - bnxt_re_dev_uninit()
   and bnxt_re_ib_uninit().

 - Simplify the code by combining the different steps to add and remove
   the device into two functions.

 - Report correct netdev link state during device register

Link: https://lore.kernel.org/r/1582731932-26574-2-git-send-email-selvin.xavier@broadcom.com


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