powerpc/powernv: Check PHB type in advance

The patch checks PHB type a bit early to save a bit cycles
for P7 because we don't support M64 for P7IOC no matter what
OPAL firmware we have.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -313,6 +313,12 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
 	const u32 *r;
 	u64 pci_addr;
 
+	/* FIXME: Support M64 for P7IOC */
+	if (phb->type != PNV_PHB_IODA2) {
+		pr_info("  Not support M64 window\n");
+		return;
+	}
+
 	if (!firmware_has_feature(FW_FEATURE_OPALv3)) {
 		pr_info("  Firmware too old to support M64 window\n");
 		return;
@@ -325,12 +331,6 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
 		return;
 	}
 
-	/* FIXME: Support M64 for P7IOC */
-	if (phb->type != PNV_PHB_IODA2) {
-		pr_info("  Not support M64 window\n");
-		return;
-	}
-
 	res = &hose->mem_resources[1];
 	res->start = of_translate_address(dn, r + 2);
 	res->end = res->start + of_read_number(r + 4, 2) - 1;