drm: fix drm PCIGART

PCI Express support broke PCIGART

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/ati_pcigart.c b/drivers/char/drm/ati_pcigart.c
index d07ce96..6d3fec1 100644
--- a/drivers/char/drm/ati_pcigart.c
+++ b/drivers/char/drm/ati_pcigart.c
@@ -205,7 +205,8 @@
 			if (gart_info->is_pcie)
 				*pci_gart = (cpu_to_le32(page_base) >> 8) | 0xc;
 			else
-				*pci_gart++ = cpu_to_le32(page_base);
+				*pci_gart = cpu_to_le32(page_base);
+			*pci_gart++;
 			page_base += ATI_PCIGART_PAGE_SIZE;
 		}
 	}