label power.stats-vendor properly

Bug: 182320246
Test: boot with power.stats-vendor labeled
Change-Id: I3f1c35218554788a6e17fa2dc94fe1f4d9950624
diff --git a/powerstats/service_contexts b/powerstats/service_contexts
new file mode 100644
index 0000000..816e63c
--- /dev/null
+++ b/powerstats/service_contexts
@@ -0,0 +1 @@
+power.stats-vendor    u:object_r:hal_power_stats_vendor_service:s0