bnx2x: Fix VF flr flow

When a VF originating from a given PF is flr-ed, that PF gets an interrupt
from the chip management and takes a part in the flr process.

This patch fixes several corner cases in which the driver performs its part
of the flr flow out-of-order, causing the FW to assert due to badly timed
messages received from the driver.

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