Mark slot as succesfully booted on boot completed

Fixes #55
diff --git a/vndk.rc b/vndk.rc
index d02fdbe..1b831ed 100644
--- a/vndk.rc
+++ b/vndk.rc
@@ -12,4 +12,4 @@
     start phh_service_cleaner
     write /sys/class/hw_power/charger/direct_charger/iin_thermal 4500
     write /sys/class/hw_power/charger/charge_data/iin_thermal 2000
-
+    exec u:r:phhsu_daemon:s0 root -- /system/bin/bootctl mark-boot-successful