drm/i915: Fix typo from e5281ccd in i915_gem_attach_phys_object()

Accessing the uninitialised obj->pages instead of the local page lead to
an OOPs.

Reported-by: Xavier Chantry <chantry.xavier@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 936ddd8..e3fc333 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4925,7 +4925,7 @@
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		src = kmap_atomic(obj_priv->pages[i]);
+		src = kmap_atomic(page);
 		dst = obj_priv->phys_obj->handle->vaddr + (i * PAGE_SIZE);
 		memcpy(dst, src, PAGE_SIZE);
 		kunmap_atomic(src);