Fixed invalid reference to DFSR_PMU constant from CortexM.
Fixed invalid reference to DFSR_PMU constant from CortexM.

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