be2net: fix access to SEMAPHORE reg

The SEMAPHORE register was being accessed from the csr BAR space. This BAR
may not be available in some Skyhawk-R configurations. Instead, access this
register via the PCI config space (it's available there too).

Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>