s390/init: add missing __init annotations

Add __init to reserve_memory_end, reserve_oldmem and remove_oldmem.
Sometimes these functions are not inlined, and then the build
complains about section mismatch.

Signed-off-by: Ilya Leoshkevich <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Vasily Gorbik <[e-mail]>

arch/s390/kernel/setup.c

···
 /*
  * Make sure that the area behind memory_end is protected
  */
-static void reserve_memory_end(void)
+static void __init reserve_memory_end(void)
 {
 	if (memory_end_set)
 		memblock_reserve(memory_end, ULONG_MAX);
···
 /*
  * Make sure that oldmem, where the dump is stored, is protected
  */
-static void reserve_oldmem(void)
+static void __init reserve_oldmem(void)
 {
 #ifdef CONFIG_CRASH_DUMP
 	if (OLDMEM_BASE)
···
 /*
  * Make sure that oldmem, where the dump is stored, is protected
  */
-static void remove_oldmem(void)
+static void __init remove_oldmem(void)
 {
 #ifdef CONFIG_CRASH_DUMP
 	if (OLDMEM_BASE)