drm/i915: Fix gen9 forcewake range table

Commit 0dd356bb ("drm/i915: Eliminate Gen9 special case")
accidentaly dropped a MMIO range between 0xc000 to 0xcfff out
of the blitter forcewake domain. Fix it.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 0dd356bb ("drm/i915: Eliminate Gen9 special case")
Reported-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1479373363-16528-1-git-send-email-tvrtko.ursulin@linux.intel.com