This commit add comments about what CLM stands for.
The motivation of this is that I think it helps understanding the code
for users who are new to the codebase (like me).
For some reason I got strange events on channel 1 (ASYNCEVENT_HEADER):
0.647329 WARN unexpected ehternet type 0x0508, expected Qualcom ether type 0x886c
This patch improves the validation of BCD WHD events to minimize the
risk for panic.
