drm/i915/gvt: fix sparse warnings on different address spaces

Add proper __iomem annotation for pointers obtained via ioremap().

Signed-off-by: Du, Changbin <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 0722d1e..a8c2405 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -269,7 +269,7 @@
 
 static u64 read_pte64(struct drm_i915_private *dev_priv, unsigned long index)
 {
-	void *addr = (u64 *)dev_priv->ggtt.gsm + index;
+	void __iomem *addr = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm + index;
 	u64 pte;
 
 #ifdef readq
@@ -284,7 +284,7 @@
 static void write_pte64(struct drm_i915_private *dev_priv,
 		unsigned long index, u64 pte)
 {
-	void *addr = (u64 *)dev_priv->ggtt.gsm + index;
+	void __iomem *addr = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm + index;
 
 #ifdef writeq
 	writeq(pte, addr);