drm/backlight: initialize struct backlight_properties properly

The power field was never correctly initialized.

[airlied: just took the two drm specific bits]

Signed-off-by: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 2b2e011..2a1625d 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -368,6 +368,7 @@
 	else
 		return -ENODEV;
 
+	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = intel_panel_get_max_backlight(dev);
 	dev_priv->backlight =