powerpc: Make add_system_ram_resources() __init

add_system_ram_resources() is a subsys_initcall.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/mem.c

@@ -507,7 +507,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
  * System memory should not be in /proc/iomem but various tools expect it
  * (eg kdump).
  */
-static int add_system_ram_resources(void)
+static int __init add_system_ram_resources(void)
 {
 	struct memblock_region *reg;