Skip net_poll and timers unless their interrupt has fired

firmware/w6300/w6300.cpp

@@ -78,7 +78,7 @@ void pio_init() {
     gpio_set_dir(PIN_INT, GPIO_IN);
     gpio_pull_up(PIN_INT);
     gpio_set_irq_enabled_with_callback(PIN_INT, GPIO_IRQ_EDGE_FALL, true,
-        [](uint, uint32_t){});
+        [](uint, uint32_t){ irq_pending = true; });
 
     pio_hw_t *pios[2] = {pio0, pio1};
     uint pio_index = 1;
@@ -490,6 +490,8 @@ std::expected<void, sock_error> close(socket_id sid) {
 
 } // namespace
 
+volatile bool irq_pending = false;
+
 void clear_interrupt(intr_kind intr) {
     set_irclr((uint8_t)intr);
     uint8_t sir = (uint8_t)((uint16_t)intr >> 8);