drm/i915: Separate cherryview from valleyview

The cherryview device shares many characteristics with the valleyview
device.  When support was added to the driver for cherryview, the
corresponding device info structure included .is_valleyview = 1.
This is not correct and leads to some confusion.

This patch changes .is_valleyview to .is_cherryview in the cherryview
device info structure and simplifies the IS_CHERRYVIEW macro.
Then where appropriate, instances of IS_VALLEYVIEW are replaced with
IS_VALLEYVIEW || IS_CHERRYVIEW or equivalent.

v2: Use IS_VALLEYVIEW || IS_CHERRYVIEW instead of defining a new macro.
    Also add followup patches to fix issues discovered during the first
    review. (Ville)
v3: Fix some style issues and one gen check. Remove CRT related changes
    as CRT is not supported on CHV. (Imre, Ville)
v4: Make a few more optimizations. (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Wayne Boyer <wayne.boyer@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449692975-14803-1-git-send-email-wayne.boyer@intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_psr.c

@@ -326,8 +326,8 @@ static bool intel_psr_match_conditions(struct intel_dp *intel_dp)
 		return false;
 	}
 
-	if (!IS_VALLEYVIEW(dev) && ((dev_priv->vbt.psr.full_link) ||
-				    (dig_port->port != PORT_A))) {
+	if (!IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev) &&
+	    ((dev_priv->vbt.psr.full_link) || (dig_port->port != PORT_A))) {
 		DRM_DEBUG_KMS("PSR condition failed: Link Standby requested/needed but not supported on this platform\n");
 		return false;
 	}
@@ -644,7 +644,7 @@ void intel_psr_single_frame_update(struct drm_device *dev,
 	 * Single frame update is already supported on BDW+ but it requires
 	 * many W/A and it isn't really needed.
 	 */
-	if (!IS_VALLEYVIEW(dev))
+	if (!IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev))
 		return;
 
 	mutex_lock(&dev_priv->psr.lock);