the only change this results in in the example binaries is in the
hackrf-jellybean/systick example, where the the check in
systick_set_clocksource for overflowing from the stm32 area gets used.
these register definitions are common to all cortex mcus. some of the
registers might not be implemented everywhere (especially the floating
point registers), but defining them does no harm.
this modification does not result in any changes in the example
binaries.
