mem-cache: Add missing includes in TreePLRU

Add missing includes to TreePLRU files.

Change-Id: Ia1e7b2aa91eec8a30b6dccf513cca37a3058b350
Reviewed-on: https://gem5-review.googlesource.com/c/13477
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
2 files changed