Update GSM_M6315.ino

Author: Tinyu-Zhao

examples/Modules/GSM_M6315/GSM_M6315.ino

@@ -29,7 +29,6 @@ void setup() {
   M5.begin();
   M5.Power.begin();
 
-  Serial.begin(115200);
   Serial2.begin(115200, SERIAL_8N1, 16, 17);
   pinMode(5, OUTPUT);
   digitalWrite(5, 1);