Also add a const version of the getPhysMem accessor so it can be used with a const System class. Change-Id: Ieccd0bd4c2c8fe69820eb1a0b0c835722334630d Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50343 Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Gabe Black <gabe.black@gmail.com> Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>