Fix warnings

Author: facchinm

cores/arduino/Interrupts.cpp

@@ -21,7 +21,7 @@
 #ifdef digitalPinToInterruptObj
 static mbed::InterruptIn* PinNameToInterruptObj(PinName P) {
   // reverse search for pinName in g_APinDescription[P].name fields
-  for (int i=0; i < PINS_COUNT; i++) {
+  for (pin_size_t i=0; i < PINS_COUNT; i++) {
     if (g_APinDescription[i].name == P) {
       return g_APinDescription[i].irq;
     }

cores/arduino/wiring.cpp

@@ -39,7 +39,7 @@ unsigned long micros() {
 
 void delay(unsigned long ms)
 {
-  wait_ms(ms);
+  thread_sleep_for(ms);
 }
 
 void delayMicroseconds(unsigned int us)

cores/arduino/wiring_analog.cpp

@@ -29,7 +29,7 @@ static int read_resolution = 10;
 #ifdef digitalPinToPwmObj
 static mbed::PwmOut* PinNameToPwmObj(PinName P) {
   // reverse search for pinName in g_APinDescription[P].name fields
-  for (int i=0; i < PINS_COUNT; i++) {
+  for (pin_size_t i=0; i < PINS_COUNT; i++) {
     if (g_APinDescription[i].name == P) {
       return g_APinDescription[i].pwm;
     }