pmdomain: renesas: rcar-gen4-sysc: Move init to postcore_initcall

Subsequent changes to genpd adds a limitation that registering a genpd OF
providers must be done after its bus registration, which is at
core_initcall. To adopt to this, let's move to a postcore_initcall.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250701114733.636510-4-ulf.hansson@linaro.org

drivers/pmdomain/renesas/rcar-gen4-sysc.c

@@ -374,4 +374,4 @@ out_put:
 	of_node_put(np);
 	return error;
 }
-early_initcall(rcar_gen4_sysc_pd_init);
+postcore_initcall(rcar_gen4_sysc_pd_init);