benchmarks/lockhammer/README.rst

Document new features and usage

- document new make targets (allvariants, etc.)
- using run-tests.sh, recording results to json files
- view-results-json.sh to examine json result files
- using a persistent hugepage (-M)
- CPU pinorders (-o)
- (Importance of disabling) CPU frequency scaling

Change-Id: I39d860f9e4829641bc00fd76f31dabc9f79964bc

Author: jty2