EEPROM: examples: fix Serial for board Leonardo

hardware/arduino/avr/libraries/EEPROM/examples/eeprom_crc/eeprom_crc.ino

@@ -14,7 +14,10 @@ void setup(){
   
   //Start serial
   Serial.begin(9600);
-  
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for Leonardo only
+  }
+
   //Print length of data to run CRC on.
   Serial.print( "EEPROM length: " );
   Serial.println( EEPROM.length() );

hardware/arduino/avr/libraries/EEPROM/examples/eeprom_get/eeprom_get.ino

@@ -23,8 +23,11 @@ void setup(){
   int eeAddress = 0; //EEPROM address to start reading from
   
   Serial.begin( 9600 );
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for Leonardo only
+  }
   Serial.print( "Read float from EEPROM: " );
-  
+
   //Get the float data from the EEPROM at position 'eeAddress'
   EEPROM.get( eeAddress, f );
   Serial.println( f, 3 );  //This may print 'ovf, nan' if the data inside the EEPROM is not a valid float.

hardware/arduino/avr/libraries/EEPROM/examples/eeprom_put/eeprom_put.ino

@@ -25,7 +25,10 @@ struct MyObject{
 void setup(){
 
   Serial.begin(9600);
-  
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for Leonardo only
+  }
+
   float f = 123.456f;  //Variable to store in EEPROM.
   int eeAddress = 0;   //Location we want the data to be put.