drm/i915/bxt: Export pooled eu info to userspace

drm/i915/bxt: Export pooled eu info to userspace

Pooled EU is a bxt only feature and kernel changes are already merged. This
feature is not yet exposed to userspace as the support was not yet
available. Beignet team expressed interest and added patches to use this.

Since we now have a user and patches to use them, expose them from the
kernel side as well.

v2: fix compile error

[1] https://lists.freedesktop.org/archives/beignet/2016-June/007698.html
[2] https://lists.freedesktop.org/archives/beignet/2016-June/007699.html

Cc: Winiarski, Michal <michal.winiarski@intel.com>
Cc: Zou, Nanhai <nanhai.zou@intel.com>
Cc: Yang, Rong R <rong.r.yang@intel.com>
Cc: Tim Gore <tim.gore@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467369782-25992-1-git-send-email-arun.siluvery@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>