s390/pm: export pm_power_off

Export pm_power_off symbol. Needed by at least one of the new device
drivers that come with CONFIG_PCI.
And all other architectures export that symbol as well.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/setup.c

@@ -16,7 +16,7 @@
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include <linux/errno.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/memblock.h>
@@ -289,6 +289,7 @@ void machine_power_off(void)
  * Dummy power off function.
  */
 void (*pm_power_off)(void) = machine_power_off;
+EXPORT_SYMBOL_GPL(pm_power_off);
 
 static int __init early_parse_mem(char *p)
 {