esp8266/espneopixel: Disable IRQs during eps.neopixel_write.

Interrupts during neopixel_write causes timing problems and therefore
wrong light patterns.  Switching off IRQs should help to keep the strict
timing schedule.

esp8266/espneopixel.c

@@ -41,6 +41,7 @@ void /*ICACHE_RAM_ATTR*/ esp_neopixel_write(uint8_t pin, uint8_t *pixels, uint32
   }
 #endif
 
+  uint32_t irq_state = mp_hal_quiet_timing_enter();
   for(t = time0;; t = time0) {
     if(pix & mask) t = time1;                             // Bit high duration
     while(((c = mp_hal_ticks_cpu()) - startTime) < period); // Wait for bit start
@@ -55,4 +56,5 @@ void /*ICACHE_RAM_ATTR*/ esp_neopixel_write(uint8_t pin, uint8_t *pixels, uint32
     }
   }
   while((mp_hal_ticks_cpu() - startTime) < period); // Wait for last bit
+  mp_hal_quiet_timing_exit(irq_state);
 }