Locking STLink for each command.
Locking STLink for each command.

- This prevents multiple threads from trying to send commands simultaneously.

mesheven/pyOCD,mbedmicro/pyOCD,mesheven/pyOCD,flit/pyOCD,mesheven/pyOCD,mbedmicro/pyOCD,flit/pyOCD,pyocd/pyOCD,pyocd/pyOCD,mbedmicro/pyOCD