hwmon: (oxp-sensors) Move tt_toggle attribute to dev_groups

hwmon: (oxp-sensors) Move tt_toggle attribute to dev_groups

A driver should not be manually adding groups in its probe function (it
will race with userspace), so replace the call to devm_device_add_groups()
to use the platform dev_groups callback instead.

This will allow for removal of the devm_device_add_groups() function.

Signed-off-by: Joaquín Ignacio Aramendía <samsagax@gmail.com>
Fixes: be144ee49127 ("hwmon: (oxp-sensors) Add tt_toggle attribute on supported boards")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230717222526.229984-2-samsagax@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>