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

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2739,6 +2739,8 @@ static const char *power_domain_str(enum intel_display_power_domain domain)
 		return "AUX_D";
 	case POWER_DOMAIN_GMBUS:
 		return "GMBUS";
+	case POWER_DOMAIN_MODESET:
+		return "MODESET";
 	case POWER_DOMAIN_INIT:
 		return "INIT";
 	default:

drivers/gpu/drm/i915/i915_drv.h

@@ -196,6 +196,7 @@ enum intel_display_power_domain {
 	POWER_DOMAIN_AUX_C,
 	POWER_DOMAIN_AUX_D,
 	POWER_DOMAIN_GMBUS,
+	POWER_DOMAIN_MODESET,
 	POWER_DOMAIN_INIT,
 
 	POWER_DOMAIN_NUM,