sched: export kick_process

lguest needs kick_process: wake_up_process() does nothing if a process
is running, which isn't sufficient (we need it in the kernel).

And lguest support is usually modular.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index f04aa96..8ec9d13 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2192,6 +2192,7 @@
 		smp_send_reschedule(cpu);
 	preempt_enable();
 }
+EXPORT_SYMBOL_GPL(kick_process);
 
 /*
  * Return a low guess at the load of a migration-source cpu weighted