hwmon: (lm77) Fix checkpatch issues

hwmon: (lm77) Fix checkpatch issues

Fixed:
ERROR: code indent should use tabs where possible
ERROR: do not use assignment in if condition
ERROR: trailing whitespace
WARNING: line over 80 characters
WARNING: please, no space before tabs
WARNING: simple_strtol is obsolete, use kstrtol instead
WARNING: simple_strtoul is obsolete, use kstrtoul instead

Modify multi-line comments to follow Documentation/CodingStyle.

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