MAINTAINERS: adjust file entry in STARFIVE JH71XX PMU CONTROLLER DRIVER

Commit f3fb1629 ("soc: starfive: Move the power-domain driver to the
genpd dir") moves:

  drivers/{soc/starfive/jh71xx_pmu.c => genpd/starfive/jh71xx-pmu.c}

However, the update to the file entry in MAINTAINERS only addresses the
move in directories, but misses the renaming from jh71xx_pmu.c to
jh71xx-pmu.c. Hence, ./scripts/get_maintainer.pl --self-test=patterns
complains about a broken reference.

Adjust the file entry in STARFIVE JH71XX PMU CONTROLLER DRIVER.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>