drm/i915: remove unused has_dma_mapping flag

After the previous patch this flag will check always clear, as it's
never set for shmem backed and userptr objects, so we can remove it.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Yeah this isn't really fixes but it's a nice cleanup to
clarify the code but not really worth the hassle of backmerging. So
just add to -fixes, we're still early in -rc.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index dcc6a88..56b52a4 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1723,9 +1723,6 @@
 
 int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
 {
-	if (obj->has_dma_mapping)
-		return 0;
-
 	if (!dma_map_sg(&obj->base.dev->pdev->dev,
 			obj->pages->sgl, obj->pages->nents,
 			PCI_DMA_BIDIRECTIONAL))
@@ -1972,10 +1969,8 @@
 
 	interruptible = do_idling(dev_priv);
 
-	if (!obj->has_dma_mapping)
-		dma_unmap_sg(&dev->pdev->dev,
-			     obj->pages->sgl, obj->pages->nents,
-			     PCI_DMA_BIDIRECTIONAL);
+	dma_unmap_sg(&dev->pdev->dev, obj->pages->sgl, obj->pages->nents,
+		     PCI_DMA_BIDIRECTIONAL);
 
 	undo_idling(dev_priv, interruptible);
 }