[S390] add smp_call_function_mask

This patch adds the s390 variant for smp_call_function_mask(). The
implementation is pretty straight forward using the wrapper
__smp_call_function_map() which already takes a cpumask_t argument.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/smp.h b/include/asm-s390/smp.h
index 218454b..c7b7432 100644
--- a/include/asm-s390/smp.h
+++ b/include/asm-s390/smp.h
@@ -90,6 +90,8 @@
 extern void cpu_die (void) __attribute__ ((noreturn));
 extern int __cpu_up (unsigned int cpu);
 
+extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
+	void *info, int wait);
 #endif
 
 #ifndef CONFIG_SMP