be2net: use CSR-BAR SEMAPHORE reg for BE2/BE3

The SLIPORT_SEMAPHORE register shadowed in the
config-space may not reflect the correct POST stage after
an EEH reset in BE2/3; it may return FW_READY state even though
FW is not ready. This causes the driver to prematurely
poll the FW mailbox and fail.

For BE2/3 use the CSR-BAR/0xac instead.

Reported-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>