f1/timer.
Added timer_ic_set_polarity to timer_common_f24 with
the enum tim_ic_pol now including trigger on both edges.
Changed timer_slave_set_polarity to use enum tim_et_pol
rather than tim_ic_pol.
In response to suggestion of stinkydiver73 on 24 March that
timers in all families have an option for triggers on both
edges, except F1.