There are multiple forcewake domains in newer architectures.
Rename 'i915_gen6_forcewake_count_info' debugfs entry to
'i915_forcewake_domains' to reflect this.

Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>