cpuidle: psci: Update init level to core_initcall()

Clients like regulators, interconnects and clocks depend on rpmh-rsc to
vote on resources and rpmh-rsc depends on psci power-domains to complete
probe. All of them are in core_initcall().

Change psci domain init level to core_initcall() to avoid probe defer from
all of the above.

Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20240217-init_level-v1-2-bde9e11f8317@quicinc.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>