kingst-la2016: rephrase comments for style, readability, and text length

Rephrase comments in the Kingst LA2016 driver to better match the sigrok
project's style. Consistently start with capitals and end in punctuation.
Use all upper case for acronyms to improve readability.

Keep text lines to an acceptable length. Use consistent open and close
phrases for multi-line comments. Drop C++ style comments. Add braces
where comments and one-line code results in multi-line branches of flow
control statements.

This commit also consistently uses lower case for hex literals, and
unobfuscates a few other literals: Use 0xff everywhere for unknown USB
addresses, prefer 1800 * 1000 over 18e5 for a 1.8 seconds interval.