RDMA/bnxt_re: Fix unconditional fence for newer adapters

Older adapters required an unconditional fence for
non-wire memory operations. Newer adapters doesn't require
this and therefore, disabling the unconditional fence.

Fixes: 1801d87b

 ("RDMA/bnxt_re: Support new 5760X P7 devices")
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/1705985677-15551-4-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>