drm/i915: Fix the device info of Pineview

Pineview doesn't has CXSR and need GTT-based hardware status page.
It fixes a X boot hung issue on Pinview since commit cfdf1f

Signed-off-by: Li Peng <peng.li@intel.com>
Acked-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>