drm/i915: Remove redundant check in i915_gem_obj_to_vma

No need to verify VMA belongs to GGTT since:

1. The function must return a normal VMA belonging to passed in VM.
2. There can only be one normal VMA for any VM.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1447329595-17495-1-git-send-email-tvrtko.ursulin@linux.intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -4484,10 +4484,8 @@ struct i915_vma *i915_gem_obj_to_vma(struct drm_i915_gem_object *obj,
 {
 	struct i915_vma *vma;
 	list_for_each_entry(vma, &obj->vma_list, vma_link) {
-		if (i915_is_ggtt(vma->vm) &&
-		    vma->ggtt_view.type != I915_GGTT_VIEW_NORMAL)
-			continue;
-		if (vma->vm == vm)
+		if (vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL &&
+		    vma->vm == vm)
 			return vma;
 	}
 	return NULL;