[XTENSA] Initialize semaphore_wake_lock

Initialize semaphore_wake_lock.

Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/kernel/semaphore.c b/arch/xtensa/kernel/semaphore.c
index d40f4b1..995c641 100644
--- a/arch/xtensa/kernel/semaphore.c
+++ b/arch/xtensa/kernel/semaphore.c
@@ -100,7 +100,7 @@
 	return ret;
 }
 
-spinlock_t semaphore_wake_lock;
+DEFINE_SPINLOCK(semaphore_wake_lock);
 
 /*
  * Semaphores are implemented using a two-way counter: