mem-cache: Create NRU Replacement Policy

Implementation of a Not Recently Used replacement policy.

Change-Id: I24ab3a6f1db6dcb756b869cfebb5c4bc544170e8
Reviewed-on: https://gem5-review.googlesource.com/9001
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/cache/replacement_policies/ReplacementPolicies.py

@@ -81,3 +81,7 @@ class BRRIPRP(BaseReplacementPolicy):
 
 class RRIPRP(BRRIPRP):
     btp = 0
+
+class NRURP(BRRIPRP):
+    btp = 0
+    max_RRPV = 1