Add ro.hdmi.cec.source.send_standby_on_sleep

Bug: 161205654
Test: manually tested that system property takes effect.

Change-Id: I0e6eb8048f05de91d96680ff1a64ce142a2f5c94
diff --git a/private/property_contexts b/private/property_contexts
index 357a56c..154a97e 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -362,10 +362,11 @@
 
 persist.radio.multisim.config u:object_r:exported3_radio_prop:s0 exact string
 
-persist.sys.hdmi.keep_awake u:object_r:hdmi_config_prop:s0 exact bool
-ro.hdmi.cec_device_types    u:object_r:hdmi_config_prop:s0 exact string
-ro.hdmi.device_type         u:object_r:hdmi_config_prop:s0 exact string
-ro.hdmi.wake_on_hotplug     u:object_r:hdmi_config_prop:s0 exact bool
+persist.sys.hdmi.keep_awake              u:object_r:hdmi_config_prop:s0 exact bool
+ro.hdmi.cec_device_types                 u:object_r:hdmi_config_prop:s0 exact string
+ro.hdmi.device_type                      u:object_r:hdmi_config_prop:s0 exact string
+ro.hdmi.wake_on_hotplug                  u:object_r:hdmi_config_prop:s0 exact bool
+ro.hdmi.cec.source.send_standby_on_sleep u:object_r:hdmi_config_prop:s0 exact enum to_tv broadcast none
 
 pm.dexopt.ab-ota                        u:object_r:exported_pm_prop:s0 exact string
 pm.dexopt.bg-dexopt                     u:object_r:exported_pm_prop:s0 exact string