bnx2x: Fix support for VFs on some PFs

Due to incorrect usage of PF macros when reading information relating to
interrupts, some PFs were erroneously unable to support VFs.

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