apply changes Nordic added to UART example between SDK 11 and 12
apply changes Nordic added to UART example between SDK 11 and 12

luetgendorf/Espruino,luetgendorf/Espruino,luetgendorf/Espruino,wilberforce/Espruino,luetgendorf/Espruino,lancernet/Espruino,lancernet/Espruino,lancernet/Espruino,lancernet/Espruino,lancernet/Espruino,luetgendorf/Espruino,wilberforce/Espruino,wilberforce/Espruino,wilberforce/Espruino,wilberforce/Espruino,luetgendorf/Espruino,wilberforce/Espruino,lancernet/Espruino,wilberforce/Espruino,lancernet/Espruino,luetgendorf/Espruino