drm/i915: Add a modeset power domain

We need a power domain for disabling DC5/DC6 around modesets to prevent
confusing the DMC.

Signed-off-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447084107-8521-8-git-send-email-patrik.jakobsson@linux.intel.com
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 397781a..916e9fe 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2739,6 +2739,8 @@
 		return "AUX_D";
 	case POWER_DOMAIN_GMBUS:
 		return "GMBUS";
+	case POWER_DOMAIN_MODESET:
+		return "MODESET";
 	case POWER_DOMAIN_INIT:
 		return "INIT";
 	default: