power-libperfmgr: Give access to radio group

The LCD and touchscreen nodes are owned by system:radio on Exynos
devices.

Change-Id: I465f68fac9e7a73392940a58ce70f9afacad47b7

hidl/power-libperfmgr/android.hardware.power@1.3-service.samsung-libperfmgr.rc

@@ -1,7 +1,7 @@
 service vendor.power-hal-1-3 /vendor/bin/hw/android.hardware.power@1.3-service.samsung-libperfmgr
     class hal
     user root
-    group system
+    group system radio
     priority -20
     interface android.hardware.power@1.0::IPower default
     interface android.hardware.power@1.1::IPower default