drm/i915: Fix some minor issues with atomic cdclk.

drm/i915: Fix some minor issues with atomic cdclk.

The check for active_crtcs == 0 was performed by the callers, when changing
the patches I forgot to remove those hunks.

This resulted in skylake scalers still not having the correct cdclk to
calculate scaling when all crtc's were dpms off.

Fixes: 1a617b77658e ("drm/i915: Keep track of the cdclk as if all crtc's were active.")
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1455614711-9045-1-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>