Fixed target type option name in cortex_m warning.
Fixed target type option name in cortex_m warning.

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