iProc config read flag has to be enabled for PAXBv2 instead of PAXB.

Fixes: f78e60a2 ("PCI: iproc: Reject unconfigured physical functions from PAXC")
Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>