sysclk-lwla: Work around short transfer quirk

sysclk-lwla: Work around short transfer quirk

Detect whether the FX2 firmware of the LWLA device exhibits the
short transfer bug. If so, work around the problem by limiting
reads to at most 64 bytes at a time. This slows down the memory
read after acquisition quite noticably, but makes the device
usable even in adverse conditions.