drm/i915/skl: gen9 uses the same bind_vma() vfuncs as gen6+

Temporary plug a BUG() while waiting for a better solution. See:

  http://lists.freedesktop.org/archives/intel-gfx/2014-January/038132.html

However Chris was looking at cleaning-up this as well, so went for the
easy intermediate solution instead.

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
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 d78695d..688dd00 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2130,6 +2130,7 @@
 	vma->obj = obj;
 
 	switch (INTEL_INFO(vm->dev)->gen) {
+	case 9:
 	case 8:
 	case 7:
 	case 6: