bnx2x: Separate VF and PF logic

Generally, the VF driver cannot access the chip, except by the
narrow window its BAR allows. Care had to be taken so the VF driver
will not reach code which accesses the chip elsewhere.
Refactor the nic_load flow into parts so it would be
easier to separate the VF-only logic from the PF-only logic.

Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>