MIPS: Make various locks static.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/sgi-ip27/ip27-nmi.c b/arch/mips/sgi-ip27/ip27-nmi.c
index 6c5a630..8682784 100644
--- a/arch/mips/sgi-ip27/ip27-nmi.c
+++ b/arch/mips/sgi-ip27/ip27-nmi.c
@@ -21,7 +21,7 @@
 
 typedef unsigned long machreg_t;
 
-DEFINE_SPINLOCK(nmi_lock);
+static DEFINE_SPINLOCK(nmi_lock);
 
 /*
  * Lets see what else we need to do here. Set up sp, gp?