MAINTAINERS: update thermal CPU cooling section

Update maintainers responsible for CPU cooling on Arm side.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Javi Merino <javi.merino@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210217115908.22547-1-lukasz.luba@arm.com