drm/i915: reduce includes in intel_display_power.h

Only include what's needed.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a7f41cf6d13ee78c0b3a7c5927680bb94edfc5fb.1667383630.git.jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_display_power.h

@@ -6,11 +6,12 @@
 #ifndef __INTEL_DISPLAY_POWER_H__
 #define __INTEL_DISPLAY_POWER_H__
 
-#include "intel_runtime_pm.h"
+#include "intel_wakeref.h"
 
 enum aux_ch;
 enum dpio_channel;
 enum dpio_phy;
+enum i915_drm_suspend_mode;
 enum port;
 struct drm_i915_private;
 struct i915_power_well;