Fix undeclared symbol warnings from sparse

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5539 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/hw/omap_clk.c b/hw/omap_clk.c
index 13d7411..3a68130 100644
--- a/hw/omap_clk.c
+++ b/hw/omap_clk.c
@@ -1101,7 +1101,7 @@
 
 /* If a clock is allowed to idle, it is disabled automatically when
  * all of clock domains using it are disabled.  */
-int omap_clk_is_idle(struct clk *clk)
+static int omap_clk_is_idle(struct clk *clk)
 {
     struct clk *chld;