hwmon: (lm92) Fix checkpatch issues

Fixed:
ERROR: code indent should use tabs where possible
ERROR: do not use assignment in if condition
ERROR: spaces required around that '<' (ctx:VxV)
ERROR: spaces required around that '=' (ctx:VxV)
ERROR: spaces required around that '*=' (ctx:VxV)
ERROR: trailing whitespace
WARNING: line over 80 characters
WARNING: please, no space before tabs
WARNING: please, no spaces at the start of a line
WARNING: simple_strtol is obsolete, use kstrtol instead

Modify multi-line comments to follow Documentation/CodingStyle.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>