MAINTAINERS: adjust entry in THERMAL/POWER_ALLOCATOR after header movement

Commit 32a7a021 ("thermal/core: Relocate the traces definition in
thermal directory") moves include/trace/events/thermal_power_allocator.h to
drivers/thermal/thermal_trace_ipa.h, but misses to adjust the file
entry for the THERMAL/POWER_ALLOCATOR section.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Adjust this file entry in THERMAL/POWER_ALLOCATOR.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230328091737.6785-1-lukas.bulwahn@gmail.com