Fixed some minor typos in comments (#1082)

* Fixed typo in the username

Author: pintman

examples/GatewayW5100MQTTClient/GatewayW5100MQTTClient.ino

@@ -96,7 +96,7 @@
 #define MY_RF24_CS_PIN 6
 #endif
 
-// Enable these if your MQTT broker requires usenrame/password
+// Enable these if your MQTT broker requires username/password
 //#define MY_MQTT_USER "username"
 //#define MY_MQTT_PASSWORD "password"
 

examples_linux/mysgw.cpp

@@ -45,7 +45,7 @@
 //#define MY_MQTT_PUBLISH_TOPIC_PREFIX "mygateway1-out"
 //#define MY_MQTT_SUBSCRIBE_TOPIC_PREFIX "mygateway1-in"
 
-// Enable these if your MQTT broker requires usenrame/password
+// Enable these if your MQTT broker requires username/password
 //#define MY_MQTT_USER "username"
 //#define MY_MQTT_PASSWORD "password"