powerpc/powernv: Use it_page_shift in TCE build

This makes use of iommu_table::it_page_shift instead of TCE_SHIFT and
TCE_RPN_SHIFT hardcoded values.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/pci.c

@@ -564,10 +564,11 @@ static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
 		proto_tce |= TCE_PCI_WRITE;
 
 	tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
-	rpn = __pa(uaddr) >> TCE_SHIFT;
+	rpn = __pa(uaddr) >> tbl->it_page_shift;
 
 	while (npages--)
-		*(tcep++) = cpu_to_be64(proto_tce | (rpn++ << TCE_RPN_SHIFT));
+		*(tcep++) = cpu_to_be64(proto_tce |
+				(rpn++ << tbl->it_page_shift));
 
 	/* Some implementations won't cache invalid TCEs and thus may not
 	 * need that flush. We'll probably turn it_type into a bit mask