drm/i915: Reduce the pointer dance of i915_is_ggtt()

The multiple levels of indirect do nothing but hinder the compiler and
the pointer chasing turns to be quite painful but painless to fix.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1456484600-11477-1-git-send-email-tvrtko.ursulin@linux.intel.com
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 8fd00d2..1328bc5 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -668,7 +668,7 @@
 	if (entry->relocation_count == 0)
 		return false;
 
-	if (!i915_is_ggtt(vma->vm))
+	if (!vma->is_ggtt)
 		return false;
 
 	/* See also use_cpu_reloc() */
@@ -687,8 +687,7 @@
 	struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;
 	struct drm_i915_gem_object *obj = vma->obj;
 
-	WARN_ON(entry->flags & __EXEC_OBJECT_NEEDS_MAP &&
-	       !i915_is_ggtt(vma->vm));
+	WARN_ON(entry->flags & __EXEC_OBJECT_NEEDS_MAP && !vma->is_ggtt);
 
 	if (entry->alignment &&
 	    vma->node.start & (entry->alignment - 1))