arch-riscv: Add an ostream operator for PrivilegeMode

This makes it easier to use the current privilege mode in error messages.

Change-Id: I425d45d3957a70d8afb6cbde18955fae1461c960
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55403
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
2 files changed