powerpc/pci: Use PCIe IP block revision register instead of compatible

Freescale PCIe IP block revision bigger than rev2.2 will also need
redefine the sequence of inbound windows. So change to use IP block
revision instead of compatible for the judgment.
Signed-off-by: NRoy Zang <tie-fei.zang@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

arch/powerpc/sysdev/fsl_pci.c

@@ -143,18 +143,20 @@ static void __init setup_pci_atmu(struct pci_controller *hose,
 	pr_debug("PCI memory map start 0x%016llx, size 0x%016llx\n",
 		 (u64)rsrc->start, (u64)resource_size(rsrc));
 
-	if (of_device_is_compatible(hose->dn, "fsl,qoriq-pcie-v2.2")) {
-		win_idx = 2;
-		start_idx = 0;
-		end_idx = 3;
-	}
-
 	pci = ioremap(rsrc->start, resource_size(rsrc));
 	if (!pci) {
 	    dev_err(hose->parent, "Unable to map ATMU registers\n");
 	    return;
 	}
 
+	if (early_find_capability(hose, 0, 0, PCI_CAP_ID_EXP)) {
+		if (in_be32(&pci->block_rev1) >= PCIE_IP_REV_2_2) {
+			win_idx = 2;
+			start_idx = 0;
+			end_idx = 3;
+		}
+	}
+
 	/* Disable all windows (except powar0 since it's ignored) */
 	for(i = 1; i < 5; i++)
 		out_be32(&pci->pow[i].powar, 0);