thermal: sysfs: Use the dev argument in instance-related show/store

thermal: sysfs: Use the dev argument in instance-related show/store

Two sysfs show/store functions for attributes representing thermal
instances, trip_point_show() and weight_store(), retrieve the thermal
zone pointer from the instance object at hand, but they may also get
it from their dev argument, which is more consistent with what the
other thermal sysfs functions do, so make them do so.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Huisong Li <lihuisong@huawei.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/1987669.PYKUYFuaPT@rjwysocki.net