hwmon: (it87) Formatting cleanup

Fix various checkpatch complaints to clean up the code and
make it easier to read.

CHECK: Do not include the paragraph about writing to the FSF
CHECK: Alignment should match open parenthesis
CHECK: Logical continuations should be on the previous line
CHECK: No space is necessary after a cast
CHECK: Please don't use multiple blank lines
CHECK: Please use a blank line after function/struct/union/enum
       declarations
CHECK: spaces preferred around that '+' (ctx:VxV)
WARNING: Missing a blank line after declarations

No functional change.
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>