hwmon: (lm83) Explain why LM82 may be misdetected as LM83

According to the March 2013 revision of the LM82 datasheet, the latest
LM82 die revision is 0x03. This was confirmed and observed with a real
chip. Further details in this revision of the LM82 datasheet suggest that
LM82 is now just a repackaged LM83. Such versions of LM82 will be detected
as LM83. Add comment to the code explaining why this may happen.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>