s390/mm: make memory_block_size_bytes available for !MEMORY_HOTPLUG

Fix this compile error for !MEMORY_HOTPLUG && NUMA:
arch/s390/built-in.o: In function `emu_setup_size_adjust':
arch/s390/numa/mode_emu.c:477: undefined reference to `memory_block_size_bytes'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/init.c

@@ -151,6 +151,15 @@ void __init free_initrd_mem(unsigned long start, unsigned long end)
 }
 #endif
 
+unsigned long memory_block_size_bytes(void)
+{
+	/*
+	 * Make sure the memory block size is always greater
+	 * or equal than the memory increment size.
+	 */
+	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
+}
+
 #ifdef CONFIG_MEMORY_HOTPLUG
 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 {
@@ -194,15 +203,6 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
 	return rc;
 }
 
-unsigned long memory_block_size_bytes(void)
-{
-	/*
-	 * Make sure the memory block size is always greater
-	 * or equal than the memory increment size.
-	 */
-	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
-}
-
 #ifdef CONFIG_MEMORY_HOTREMOVE
 int arch_remove_memory(u64 start, u64 size)
 {