Wire: Use 72 bit buf

Author: giulcioffi

libraries/Wire/Wire.cpp

@@ -136,7 +136,7 @@ void arduino::MbedI2C::receiveThd() {
 			case mbed::I2CSlave::WriteGeneral:
 			case mbed::I2CSlave::WriteAddressed:
 				rxBuffer.clear();
-				char buf[16];
+				char buf[72];
 				while (1) {
 					int c = slave->read(buf, sizeof(buf));
 					for (int i = 0; i < c; i++) {