hwmon: (lm78) Fix checkpatch issues

Fixed:
ERROR: code indent should use tabs where possible
ERROR: do not use assignment in if condition
ERROR: space prohibited before that close parenthesis ')'
ERROR: space required after that ',' (ctx:VxV)
ERROR: spaces required around that '<' (ctx:VxV)
ERROR: spaces required around that '==' (ctx:VxV)
ERROR: trailing statements should be on next line
ERROR: trailing whitespace
WARNING: simple_strtol is obsolete, use kstrtol instead
WARNING: simple_strtoul is obsolete, use kstrtoul instead

Modify multi-line comments to follow Documentation/CodingStyle.

Not fixed (false positive):
ERROR: Macros with multiple statements should be enclosed in a do - while loop

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