Removed magic numbers for mm_ram addresses and added a cycle counter

Created by: silabs-mateilga

Signed-off-by: Marton Teilgard mateilga@silabs.com

The magic numbers used to signify the mm_ram addresses have been made in to parameters for readability.

A cycle counter has been added to mm_ram. The motivation for this is to enable benchmarks running on the core to access and record the cycle count for a given testcase, which will be necessary for implementing EMBench and Coremark in core-v-verif.

This PR is relevant to issues #494 (closed) and #495 (closed).