AP_HAL_Linux: extended panic handling with RCInput deinitialization

The issue has already come up. There's no deinitialization mechanisms at the moment. As APM is rather software than firmware on Linux, there're some clean-up work that needs to be done. This commit triggers deinitialization of RCInput on a panic.

libraries/AP_HAL_Linux/Scheduler.cpp

@@ -394,6 +394,7 @@ void LinuxScheduler::panic(const prog_char_t *errormsg)
 {
     write(1, errormsg, strlen(errormsg));
     write(1, "\n", 1);
+    hal.rcin->deinit();
     hal.scheduler->delay_microseconds(10000);
     exit(1);
 }