sm8350-common: config.fs: init: add AID_VENDOR_FASTRPC group for fastrpc

Add AID_VENDOR_FASTRPC group, so that fastrpc clients can be in
this group to get extra privileges on the remote subsystem, like
higher thread priority.

Change-Id: Icb8e418cfe66d696cad9d608d30f4b3f2a02bef8

config.fs

@@ -19,6 +19,9 @@ value:2906
 [AID_VENDOR_THERMAL]
 value:2907
 
+[AID_VENDOR_FASTRPC]
+value:2908
+
 [vendor/bin/hw/android.hardware.bluetooth@1.0-service-qti]
 mode: 0755
 user: AID_BLUETOOTH