hwmon: (isl28022) Use per-client debugfs entry

The I2C core now offers a debugfs-directory per client. Use it and
remove the custom handling.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20250123160347.44635-1-wsa+renesas@sang-engineering.com


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