drm/i915/chv: Remove Wait for a previous gfx force-off

On CHV, PUNIT team confirmed that 'VLV_GFX_CLK_STATUS_BIT' is not a
sticky bit and it will always be set. So ignore Check for previous
Gfx force off during suspend and allow the force clk as part S0ix
Sequence

Signed-off-by: Deepak S <deepak.s@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>