RDMA/bnxt_re: Add support for unique GID

RDMA/bnxt_re: Add support for unique GID

- RawEth QP requires unique GID so that per function stats_ctx
  is not polluted by packets mirrored to RoCE vnic.
- Added support to add unique GID when RawEth type QP is created.
- Added support to destroy unique GID when RawEth type QP is
  destroyed.
- Allocated exclusive stats_ctx to use for RawEth type QP.

Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com>
Reviewed-by: Kashyap Desai <kashyap.desai@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Link: https://patch.msgid.link/20250822040801.776196-6-kalesh-anakkur.purayil@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>