bnxt_en: Fix compile errors when CONFIG_BNXT_SRIOV is not set.

struct bnxt_pf_info needs to be always defined.  Move bnxt_update_vf_mac()
to bnxt_sriov.c and add some missing #ifdef CONFIG_BNXT_SRIOV.

Reported-by: Jim Hull <jim.hull@hpe.com>
Tested-by: Jim Hull <jim.hull@hpe.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>