[POWERPC] Constify the of_device_id passed to of_platform_bus_probe

This will allow us to declare const all the statically declared arrrays
of these.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/of_platform.h b/include/asm-powerpc/of_platform.h
index d20a4cd..1bce5ef 100644
--- a/include/asm-powerpc/of_platform.h
+++ b/include/asm-powerpc/of_platform.h
@@ -32,7 +32,7 @@
 #define OF_NO_DEEP_PROBE ((struct of_device_id *)-1)
 
 extern int of_platform_bus_probe(struct device_node *root,
-				 struct of_device_id *matches,
+				 const struct of_device_id *matches,
 				 struct device *parent);
 
 extern struct of_device *of_find_device_by_phandle(phandle ph);