allocate secind serial to AHBO
disable DFU by default
add dfu_enable to config
Merge pull request #530 from wolfmanjm/feature/disable-dfu-option

Feature/disable dfu option
update firmware.bin with dfu disabled
add DISABLEMSD to options allowed on make command line
Merge pull request #531 from wolfmanjm/upstreamedge

add DISABLEMSD to options allowed on make command line
add a disablemsd version of firmware.bin
fix ls
Merge pull request #532 from wolfmanjm/upstreamedge

fix ls