PCI: Only check the HT capability bits in mpic.c

Only compare the exact HT capability bits against HT_CAPTYPE_IRQ,
this is a little paranoid, but doesn't hurt.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/powerpc/sysdev/mpic.c

@@ -390,7 +390,7 @@ static void __init mpic_scan_ht_pic(struct mpic *mpic, u8 __iomem *devbase,
 		u8 id = readb(devbase + pos + PCI_CAP_LIST_ID);
 		if (id == PCI_CAP_ID_HT) {
 			id = readb(devbase + pos + 3);
-			if (id == HT_CAPTYPE_IRQ)
+			if ((id & HT_5BIT_CAP_MASK) == HT_CAPTYPE_IRQ)
 				break;
 		}
 	}