mimxrt/mphalport: Run events at least once in mp_hal_delay_ms.

Per the docs for `time.sleep()` and `time.sleep_ms()`.  This gets the
`tests/micropython/schedule_sleep.py` test working when using the native
emitter.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

ports/mimxrt/mphalport.h

@@ -123,6 +123,9 @@ static inline mp_uint_t mp_hal_ticks_us(void) {
 }
 
 static inline void mp_hal_delay_ms(mp_uint_t ms) {
+    // This function must run events at least once, so do that now.
+    mp_event_handle_nowait();
+
     uint64_t us = (uint64_t)ms * 1000;
     ticks_delay_us64(us);
 }