drm/i915: Add frame buffer compression support on Ironlake mobile

About 0.2W power can be saved on one HP laptop.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.c

@@ -134,7 +134,7 @@ static const struct intel_device_info intel_ironlake_d_info = {
 
 static const struct intel_device_info intel_ironlake_m_info = {
 	.is_ironlake = 1, .is_mobile = 1, .is_i965g = 1, .is_i9xx = 1,
-	.need_gfx_hws = 1, .has_rc6 = 1,
+	.need_gfx_hws = 1, .has_fbc = 1, .has_rc6 = 1,
 	.has_hotplug = 1,
 };