As per guidelines in HACKING, the protocol "commands"/items should be ALLCAPS,
thus change 'data' to 'DATA'. Also, fix MX25Lxx05D protocol decoder
accordingly, currently the only one we have which stacks on top of SPI.
Add a new 'CS-CHANGE' output protocol item, which is sent upon every
change of the CS# pin value (either 0->1, or vice versa). This is needed
by various higher-level PDs.