drm/i915: WARN if we receive any rps interrupts on gen>9

This extends

commit 132f3f17
Author: Imre Deak <imre.deak@intel.com>
Date:   Mon Nov 10 15:34:33 2014 +0200

    drm/i915: WARN if we receive any gen9 rps interrupts

to GEN>9 platforms as suggested by Paulo.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>