pmdomain: core: Don't clear suspended_count at genpd_prepare()

There is no longer any need to clear genpd->suspended_count in
genpd_prepare(), as it should be correctly incremented and decremented for
all cases. In fact, if the counter isn't correctly managed we would be
hiding a problem that we shouldn't. Therefore, let's not clear it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20240412104208.74361-2-ulf.hansson@linaro.org