drm/i915/kbl: Add REVID macro

Add REVID macro for kbl to limit wa applicability to particular
revision range.
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-4-git-send-email-mika.kuoppala@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -2717,6 +2717,12 @@ struct drm_i915_cmd_table {
 
 #define IS_BXT_REVID(p, since, until) (IS_BROXTON(p) && IS_REVID(p, since, until))
 
+#define KBL_REVID_A0		0x0
+#define KBL_REVID_B0		0x1
+
+#define IS_KBL_REVID(p, since, until) \
+	(IS_KABYLAKE(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