Introduce eecache_editor.pl tool

This commit introduces the eecache_editor tool which can be used
to take an ecc-less EECACHE section from pnor and provide human
readable information about its contents, read specific cache entries
out, and to clear/overwite exists entries in a given cache.

Change-Id: I4c74f5172e7a681d34b3b654158dc8d76332107a
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/80622
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Matt Derksen <mderkse1@us.ibm.com>
Reviewed-by: Chen Du <duchen@us.ibm.com>
Reviewed-by: Daniel M Crowell <dcrowell@us.ibm.com>