Fix PCI<->OF matching on G5 AGP bus

(I noticed more recent patches got in while this one didn't, just re-sending this one in case it went unnoticed :)

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Strangely, I though I fixed that a long time ago, but it was still broken in the current tree... So drivers like radeonfb fail to find the OF device matching a given PCI device on the G5 AGP bus because of some bus renumbering tricks. This patch fixes the problem by fixing the bus numbers in the OF node. This corrects radeonfb and other drivers looking for EDID / PLL datas in the OF node.

===== arch/ppc64/kernel/pmac_pci.c 1.3 vs edited =====

@@ -719,6 +719,17 @@
 	/* Setup the linkage between OF nodes and PHBs */ 
 	pci_devs_phb_init();
 
+	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
+	 * assume there is no P2P bridge on the AGP bus, which should be a
+	 * safe assumptions hopefully.
+	 */
+	if (u3_agp) {
+		struct device_node *np = u3_agp->arch_data;
+		np->busno = 0xf0;
+		for (np = np->child; np; np = np->sibling)
+			np->busno = 0xf0;
+	}
+
 	pmac_check_ht_link();
 
 	/* Tell pci.c to use the common resource allocation mecanism */