(platform) stm32f3-agents: Fix transmitter
(platform) stm32f3-agents: Fix transmitter

Now can be used for more than two boards

embox/embox,Kakadu/embox,Kakadu/embox,embox/embox,Kakadu/embox,embox/embox,Kakadu/embox,Kakadu/embox,embox/embox,embox/embox,embox/embox,Kakadu/embox,Kakadu/embox