thermal/drivers/exynos: Wwitch from workqueue-driven interrupt handling to threaded interrupts

The workqueue boilerplate is mostly one-to-one what the threaded
interrupts do.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Mateusz Majewski <m.majewski2@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231201095625.301884-4-m.majewski2@samsung.com