hwmon: (via686a) Introduce a #define for the driver name and use it

hwmon: (via686a) Introduce a #define for the driver name and use it

Make use of the cpp symbol DRIVER_NAME to set the driver's name and use
it instead of all explicit usages of the same string. Also make use of
it instead of sis5595_driver.driver.name which breaks a cyclic dependency
between sis5595_probe() and sis5595_driver that in the next commit allows
to drop some forward declarations. For an amd64 allyesconfig this even
reduces the size of the driver by 3 bytes.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220924135738.234051-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>