Set the CV DMX-Channel for backlight port visible, but read-only.

git-svn-id: http://svn.code.sf.net/p/jbidibc/code@796 87107999-b52a-42af-a34b-1e85ba8a0939
[#44] Allow configuration of PortParam values in simulation for LPORT and BACKLIGHT.

git-svn-id: http://svn.code.sf.net/p/jbidibc/code@797 87107999-b52a-42af-a34b-1e85ba8a0939