drm/i915/chv: Fix "drm/i915/chv: Add a bunch of pre production workarounds"

Correct a merge mishap in commit e4443e45

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Wa*:chv belongs in cherryview_enable_rps, not gen8_enable_rps.

Signed-off-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>