hwmon: (gl520sm) Various cleanups

* Drop trailing spaces
* Drop unused driver ID
* Drop stray backslashes in macros
* Rename new_client to client
* Drop redundant initializations to 0

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>