bnxt_en: use SWITCHDEV_SET_OPS() for setting vf_rep_switchdev_ops

This fixes the build error:
‘struct net_device’ has no member named ‘switchdev_ops’

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: c124a62f ("bnxt_en: add support for port_attr_get and and get_phys_port_name")
Signed-off-by: Sathya Perla <sathya.perla@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>