dm: mark function lists static

Add a couple of statics.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 466a6bf..5f0f559 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -181,7 +181,7 @@
 	DMINFO("cleaned up");
 }
 
-int (*_inits[])(void) __initdata = {
+static int (*_inits[])(void) __initdata = {
 	local_init,
 	dm_target_init,
 	dm_linear_init,
@@ -189,7 +189,7 @@
 	dm_interface_init,
 };
 
-void (*_exits[])(void) = {
+static void (*_exits[])(void) = {
 	local_exit,
 	dm_target_exit,
 	dm_linear_exit,