rootdir: init.rc: add drmrpc to surfaceflinger supplemental groups

This is necessary for some HWC hals to be able to communicate with
secure side to grant protected access to hardware owned by the
hwc. This is necessary on some architectures to grant access to
secure buffers to overlay/csc hardware

Change-Id: I4e4becba5b4a80310ce8932edea5d0d046fa9b00
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/rootdir/init.rc b/rootdir/init.rc
index e9abadd..e01a5af 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -437,7 +437,7 @@
 service surfaceflinger /system/bin/surfaceflinger
     class main
     user system
-    group graphics
+    group graphics drmrpc
     onrestart restart zygote
 
 service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server