drm/i915: Remove the IS_SNB_GT1 define

The last (only?) user of this was removed in:

  commit 2208d655
  Author: Daniel Vetter <daniel.vetter@ffwll.ch>
  Date:   Fri Nov 14 09:25:29 2014 +0100

    drm/i915: drop WaSetupGtModeTdRowDispatch:snb
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -2369,9 +2369,6 @@ struct drm_i915_cmd_table {
 #define IS_IVB_GT1(dev)		(INTEL_DEVID(dev) == 0x0156 || \
 				 INTEL_DEVID(dev) == 0x0152 || \
 				 INTEL_DEVID(dev) == 0x015a)
-#define IS_SNB_GT1(dev)		(INTEL_DEVID(dev) == 0x0102 || \
-				 INTEL_DEVID(dev) == 0x0106 || \
-				 INTEL_DEVID(dev) == 0x010A)
 #define IS_VALLEYVIEW(dev)	(INTEL_INFO(dev)->is_valleyview)
 #define IS_CHERRYVIEW(dev)	(INTEL_INFO(dev)->is_valleyview && IS_GEN8(dev))
 #define IS_HASWELL(dev)	(INTEL_INFO(dev)->is_haswell)