bnxt_en: Register devlink irrespective of firmware spec version

This will allow to register for devlink port and use port features.
Also register params only if firmware spec version is at least 0x10600
which will support reading/setting numbered variables in NVRAM.

Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>