RDMA/bnxt_re: Get rid of custom module reference counting

Instead of manually messing with parent driver module reference counting
rely on export symbol mechanism to ensure that proper probe/remove chain
is performed.

Link: https://lore.kernel.org/r/20210401065715.565226-4-leon@kernel.org


Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Acked-By: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>