powerpc/iommu: Update constant names to reflect their hardcoded page size

The powerpc iommu uses a hardcoded page size of 4K. This patch changes
the name of the IOMMU_PAGE_* macros to reflect the hardcoded values. A
future patch will use the existing names to support dynamic page
sizes.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index bac289a..7f4d857 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -564,7 +564,7 @@
 {
 	tbl->it_blocksize = 16;
 	tbl->it_base = (unsigned long)tce_mem;
-	tbl->it_offset = dma_offset >> IOMMU_PAGE_SHIFT;
+	tbl->it_offset = dma_offset >> IOMMU_PAGE_SHIFT_4K;
 	tbl->it_index = 0;
 	tbl->it_size = tce_size >> 3;
 	tbl->it_busno = 0;
@@ -761,7 +761,7 @@
 
 static int __init tce_iommu_bus_notifier_init(void)
 {
-	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE);
+	BUILD_BUG_ON(PAGE_SIZE < IOMMU_PAGE_SIZE_4K);
 
 	bus_register_notifier(&pci_bus_type, &tce_iommu_bus_nb);
 	return 0;