[PATCH] sn2: set iommu bounce limit

From: Jes Sorensen <jes@trained-monkey.org>

The following patch sets the IOMMU bounce limit on the SN2 which is require
to avoid some ISA checks in ll_rw_blk.c causing a BUG_ON().

arch/ia64/sn/io/machvec/pci_bus_cvlink.c

@@ -805,6 +805,11 @@ sn_pci_init (void)
 	if (!ia64_platform_is("sn2") || IS_RUNNING_ON_SIMULATOR())
 		return 0;
 
+	/*
+	 * This is needed to avoid bounce limit checks in the blk layer
+	 */
+	ia64_max_iommu_merge_mask = ~PAGE_MASK;
+
 	/*
 	 * set pci_raw_ops, etc.
 	 */