drm/i915: Remove i915_gem_obj_size

Only caller is i915_gem_obj_ggtt_size which only cares about
GGTT so simplify it and implement under that name.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 44950cc..ae31d4e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5309,23 +5309,18 @@
 	return false;
 }
 
-unsigned long i915_gem_obj_size(struct drm_i915_gem_object *o,
-				struct i915_address_space *vm)
+unsigned long i915_gem_obj_ggtt_size(struct drm_i915_gem_object *o)
 {
-	struct drm_i915_private *dev_priv = o->base.dev->dev_private;
 	struct i915_vma *vma;
 
-	WARN_ON(vm == &dev_priv->mm.aliasing_ppgtt->base);
-
-	BUG_ON(list_empty(&o->vma_list));
+	GEM_BUG_ON(list_empty(&o->vma_list));
 
 	list_for_each_entry(vma, &o->vma_list, obj_link) {
 		if (vma->is_ggtt &&
-		    vma->ggtt_view.type != I915_GGTT_VIEW_NORMAL)
-			continue;
-		if (vma->vm == vm)
+		    vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL)
 			return vma->node.size;
 	}
+
 	return 0;
 }