drm/i915/icl: add the main CDCLK functions

This commit adds the basic CDCLK functions, but it's still missing
pieces of the display initialization sequence.

v2:
 - Implement the voltage levels.
 - Rebase.
v3:
 - Adjust to the new "bypass" clock (Imre).
 - Call intel_dump_cdclk_state() too.
 - Rename a variable to avoid confusion.
 - Simplify the DVFS part.
v4:
 - Remove wrong bit definition (James).
 - Also drive-by fix the coding style for the register definition we
   touched.
v5:
 - Comment style (checkpatch).

Cc: James Ausmus <james.ausmus@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: James Ausmus <james.ausmus@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180206193346.18272-1-paulo.r.zanoni@intel.com
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f894e17..5853d92 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1323,6 +1323,8 @@ void cnl_init_cdclk(struct drm_i915_private *dev_priv);
 void cnl_uninit_cdclk(struct drm_i915_private *dev_priv);
 void bxt_init_cdclk(struct drm_i915_private *dev_priv);
 void bxt_uninit_cdclk(struct drm_i915_private *dev_priv);
+void icl_init_cdclk(struct drm_i915_private *dev_priv);
+void icl_uninit_cdclk(struct drm_i915_private *dev_priv);
 void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv);
 void intel_update_max_cdclk(struct drm_i915_private *dev_priv);
 void intel_update_cdclk(struct drm_i915_private *dev_priv);