kingst-la2016: renames to better reflect sequence of activities

kingst-la2016: renames to better reflect sequence of activities

The previous implementation started on a single model with lots of
experiments, and could benefit from a cleanup after more knowledge was
gathered. Rename variables and routines to better reflect what actually
is happening, use more suitable data types. Drop unused devc members.
Fixup typos in diagnostics, protect against MSB issues in bitmasks.

The USB scan just yields one of the supported devices, its model is
unknown at this time. The list of enabled channels is determined upon
acquisition start when the trigger configuration gets created. The
device executes captures in hardware to internal RAM, while the driver
waits for the acquisition to complete, before downloading sample data
to the PC. Feeding sample data to the session ends when the data is
exhausted (a good condition is yet to get found). An optional trigger
marker is put into the stream of samples but only if a trigger was
configured.