thermal/drivers/imx: Remove get_trip_temp ops

The i.MX thermal sensor uses the generic trip points. The thermal
framework can return the critical temperature directly.

Remove the pointless get_trip_temp ops.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20230309092821.1590586-1-daniel.lezcano@linaro.org


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>