Give Processors a run() function.

So main() can call it, start a Processor linked in to the baseband binary.

firmware/baseband/proc_nfm_audio.cpp

@@ -23,6 +23,8 @@
 
 #include "audio_output.hpp"
 
+#include "event_m4.hpp"
+
 #include <cstdint>
 #include <cstddef>
 
@@ -93,3 +95,8 @@ void NarrowbandFMAudio::capture_config(const CaptureConfigMessage& message) {
 		audio_output.set_stream(nullptr);
 	}
 }
+
+void run() {
+	EventDispatcher event_dispatcher { std::make_unique<NarrowbandFMAudio>() };
+	event_dispatcher.run();
+}