Update DW1000.cpp
Update DW1000.cpp

While using the library with an ESP12e, the SPI clock has to be changed to 20 MHz as 16 Mhz can not be generated while running with 80 MHz.
Alenux55/arduino-dw1000,thotro/arduino-dw1000,thotro/arduino-dw1000,Alenux55/arduino-dw1000