base: Build caching into the AddrRangeMap class

base: Build caching into the AddrRangeMap class

Rather than have each consumer of the AddrRangeMap implement caching
lookups on their own, this change adds a centralized mechanism to the
AddrRangeMap class itself.

Some benefits of this approach are that the cache handles deleted
entries correctly/automatically, the cache is maintained by
adding/removing entries from a linked list rather than moving elements
in an array and checking valid bits, and it's easy to enable in places
which might otherwise not bother with caching. The amount of caching
is tunable to balance overhead with improved lookup performance.

Change-Id: Ic25997e23de4eea501e47f039bb52ed0502c58d2
Reviewed-on: https://gem5-review.googlesource.com/5242
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>