drm/i915/cnl: add IS_CNL_REVID macro

We're going to use it in the next commits.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1496781040-20888-5-git-send-email-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -2846,6 +2846,12 @@ intel_info(const struct drm_i915_private *dev_priv)
 #define IS_GLK_REVID(dev_priv, since, until) \
 	(IS_GEMINILAKE(dev_priv) && IS_REVID(dev_priv, since, until))
 
+#define CNL_REVID_A0		0x0
+#define CNL_REVID_B0		0x1
+
+#define IS_CNL_REVID(p, since, until) \
+	(IS_CANNONLAKE(p) && IS_REVID(p, since, until))
+
 /*
  * The genX designation typically refers to the render engine, so render
  * capability related checks should use IS_GEN, while display and other checks