arch-riscv: fixed formatting.

Change-Id: I134993a4aced07e75bf62fec56081b0f9d8fc18c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/26986
Tested-by: kokoro <noreply+kokoro@google.com>
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

src/arch/riscv/isa.hh

@@ -4,6 +4,7 @@
  * Copyright (c) 2014 Sven Karlsson
  * Copyright (c) 2016 RISC-V Foundation
  * Copyright (c) 2016 The University of Virginia
+ * Copyright (c) 2020 Barkhausen Institut
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -52,7 +53,8 @@ class EventManager;
 namespace RiscvISA
 {
 
-enum PrivilegeMode {
+enum PrivilegeMode
+{
     PRV_U = 0,
     PRV_S = 1,
     PRV_M = 3