change return type of micros() and millis()

Fixes: https://github.com/espressif/arduino-esp32/issues/384

cores/esp32/esp32-hal-misc.c

@@ -30,11 +30,11 @@ void yield()
 
 portMUX_TYPE microsMux = portMUX_INITIALIZER_UNLOCKED;
 
-uint32_t IRAM_ATTR micros()
+unsigned long IRAM_ATTR micros()
 {
-    static uint32_t lccount = 0;
-    static uint32_t overflow = 0;
-    uint32_t ccount;
+    static unsigned long lccount = 0;
+    static unsigned long overflow = 0;
+    unsigned long ccount;
     portENTER_CRITICAL_ISR(&microsMux);
     __asm__ __volatile__ ( "rsr     %0, ccount" : "=a" (ccount) );
     if(ccount < lccount){
@@ -45,7 +45,7 @@ uint32_t IRAM_ATTR micros()
     return overflow + (ccount / CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ);
 }
 
-uint32_t IRAM_ATTR millis()
+unsigned long IRAM_ATTR millis()
 {
     return xTaskGetTickCount() * portTICK_PERIOD_MS;
 }

cores/esp32/esp32-hal.h

@@ -61,8 +61,8 @@ void yield(void);
 #include "esp32-hal-bt.h"
 #include "esp_system.h"
 
-uint32_t micros();
-uint32_t millis();
+unsigned long micros();
+unsigned long millis();
 void delay(uint32_t);
 void delayMicroseconds(uint32_t us);