drm/i915: Use HAS_PCH_SPLIT to determine correct devices

Do some further clean up based on the initial review of
drm/i915: Separate cherryview from valleyview.

In this case check for '(GEN7 || GEN8) && HAS_PCH_SPLIT' since we're
reading FUSE_STRAP and SFUSE_STRAP which live in the PCH.

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/1449514270-15171-3-git-send-email-wayne.boyer@intel.comReviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/i915/i915_dma.c

@@ -794,7 +794,7 @@ static void intel_device_info_runtime_init(struct drm_device *dev)
 		info->num_pipes = 0;
 	} else if (info->num_pipes > 0 &&
 		   (INTEL_INFO(dev)->gen == 7 || INTEL_INFO(dev)->gen == 8) &&
-		   !(IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))) {
+		   HAS_PCH_SPLIT(dev)) {
 		u32 fuse_strap = I915_READ(FUSE_STRAP);
 		u32 sfuse_strap = I915_READ(SFUSE_STRAP);