Fixed CortexM.available_breakpoint_count property.
Fixed CortexM.available_breakpoint_count property.

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