thermal: hisi: Use thermal_zone_for_each_trip() in hisi_thermal_register_sensor()

Modify hisi_thermal_register_sensor() to use thermal_zone_for_each_trip()
for walking trip points instead of iterating over trip indices and using
thermal_zone_get_trip() to get a struct thermal_trip pointer from a trip
index.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/1994088.PYKUYFuaPT@rjwysocki.net


[ rjw: Dropped two unused local variables ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>