config, arm, power: Example to report the power for the L2 Cache

config, arm, power: Example to report the power for the L2 Cache

This patch add an example to demonstrate how to report the power for the L2
Cache of the big cluster separately ,it decouples the L2 contributions from
the CPU power equation

Signed-off-by: Sherif Elhabbal <elhabbalsherif@gmail.com>
Change-Id: Idde43c8bcb10df9d44d20282eaf21ce87a9d3f58
Reviewed-on: https://gem5-review.googlesource.com/12684
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Anouk Van Laer <anouk.vanlaer@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>