drm/i915: get runtime PM reference around GEM set_caching IOCTL
drm/i915: get runtime PM reference around GEM set_caching IOCTL

After Damien's D3 fix I started to get runtime suspend residency for the
first time and that revealed a breakage on the set_caching IOCTL path
that accesses the HW but doesn't take an RPM ref. Fix this up.

Signed-off-by: Imre Deak <fbd5edba1988036c8923f0cca0cce6ac4811db29@intel.com>
Reviewed-by: Paulo Zanoni <cc0e04a2103c45cd195651d976f79813d0f66bdf@intel.com>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org
Link: http://patchwork.freedesktop.org/patch/msgid/1446665132-22491-1-git-send-email-fbd5edba1988036c8923f0cca0cce6ac4811db29@intel.com
Signed-off-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs