trusty: keymaster: remove unnecessary group from trusty KM3 HAL service

Test: VtsHalKeymasterV3_0TargetTest
Change-Id: Ib943a9aa5a0cab27913173a68932db651e991907
diff --git a/trusty/keymaster/3.0/android.hardware.keymaster@3.0-service.trusty.rc b/trusty/keymaster/3.0/android.hardware.keymaster@3.0-service.trusty.rc
index e9d3054..503f3de 100644
--- a/trusty/keymaster/3.0/android.hardware.keymaster@3.0-service.trusty.rc
+++ b/trusty/keymaster/3.0/android.hardware.keymaster@3.0-service.trusty.rc
@@ -1,4 +1,4 @@
 service vendor.keymaster-3-0 /vendor/bin/hw/android.hardware.keymaster@3.0-service.trusty
     class early_hal
     user nobody
-    group system drmrpc
+    group drmrpc