This patch modifies the instructions that lead users to modify predefined
scenario XMLs under ``misc/config_tools/data`` which is not a preferred
way. It is recommended to make and edit a local copy, instead.
Also fixes a few references to ``misc/vm_configs`` which has been moved.
v2:
* fix typos in paths
* explain on the candidate values of ``port_base`` and ``irq`` fields
Tracked-On: #5644
Signed-off-by: Junjie Mao <junjie.mao@intel.com>