drm/i915/icl: Add initial Icelake definitions.

Icelake is an IntelĀ® Processor containing an IntelĀ® Graphics
Controller.

This is just an initial Icelake definition. PCI IDs, Icelake support
and new features coming in following patches.

v2: Add .ddb_size and .has_guc (Michal Wajdeczko).
v3: Add the ICL_FEATURES macro (Kelvin Gardiner).
v4 (from Paulo): Add missing __initconst (Paulo) and say "graphics
controller" instead of something that looks like an official marketing
name but isn't (Chris).

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180111180010.24357-3-paulo.r.zanoni@intel.com
diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
index 49cb27b..9542018 100644
--- a/drivers/gpu/drm/i915/intel_device_info.h
+++ b/drivers/gpu/drm/i915/intel_device_info.h
@@ -69,6 +69,8 @@ enum intel_platform {
 	INTEL_COFFEELAKE,
 	/* gen10 */
 	INTEL_CANNONLAKE,
+	/* gen11 */
+	INTEL_ICELAKE,
 	INTEL_MAX_PLATFORMS
 };