allow flash to NRF51
allow flash to NRF51

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