stm32/softtimer: Add soft_timer_reinsert() helper function.

And call mp_pairheap_init_node() in soft_timer_static_init() so that
reinsert can be called after static_init.
Signed-off-by: Damien George <damien@micropython.org>

ports/stm32/softtimer.c

@@ -122,6 +122,7 @@ void soft_timer_gc_mark_all(void) {
 }
 
 void soft_timer_static_init(soft_timer_entry_t *entry, uint16_t mode, uint32_t delta_ms, void (*cb)(soft_timer_entry_t *)) {
+    mp_pairheap_init_node(soft_timer_lt, &entry->pairheap);
     entry->flags = 0;
     entry->mode = mode;
     entry->delta_ms = delta_ms;

ports/stm32/softtimer.h

@@ -56,4 +56,11 @@ void soft_timer_static_init(soft_timer_entry_t *entry, uint16_t mode, uint32_t d
 void soft_timer_insert(soft_timer_entry_t *entry, uint32_t initial_delta_ms);
 void soft_timer_remove(soft_timer_entry_t *entry);
 
+// The timer will be reinserted into the heap so that it is called after initial_delta_ms milliseconds.
+// After that, if it's periodic, it will continue to be called every entry->delta_ms milliseconds.
+static inline void soft_timer_reinsert(soft_timer_entry_t *entry, uint32_t initial_delta_ms) {
+    soft_timer_remove(entry);
+    soft_timer_insert(entry, initial_delta_ms);
+}
+
 #endif // MICROPY_INCLUDED_STM32_SOFTTIMER_H