Removing default flow control for BL652

Author: Ashok Rao

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/mbed_lib.json

@@ -63,7 +63,7 @@
                 "NRF52_PAN_64"
             ],
             "target.lf_clock_src": "NRF_LF_SRC_RC",
-            "target.console-uart-flow-control": "RTSCTS"
+            "target.console-uart-flow-control": null
         },
         "MTB_UBLOX_NINA_B1": {
             "target.macros_add": [