Disable the cell AUX UART by default on EP_AGORA

Author: Chris Trowbridge

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/TARGET_MCU_NRF52840/TARGET_EP_AGORA/ONBOARD_TELIT_ME910.cpp

@@ -114,7 +114,7 @@ nsapi_error_t ONBOARD_TELIT_ME910::init()
     // AT#PORTCFG=0
     // Set command allows to connect Service Access Points to the external physical ports giving a great
     // flexibility. Examples of Service Access Points: AT Parser Instance #1, #2, #3, etc..
-    _at->at_cmd_discard("#PORTCFG", "=3");
+    _at->at_cmd_discard("#PORTCFG", "=0");
 
     // AT&W&P
     // - AT&W: Execution command stores on profile <n> the complete configuration of the device. If