uncommon fork' in flr-capable devices to fail.

This patch resolves this, as well as fixing the flow for hypervisors which
disable flr capabilities from functions as they pass them as PDA to VMs,
as we cannot base the flow on the pci configuration space.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
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>