clk: Constify parent name arrays

Drivers should be able to declare their arrays of parent names as const
so the APIs need to accept const arguments.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
[mturquette@linaro.org: constified gate]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index f19fee0..e9c8b98 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -30,7 +30,7 @@
 	const struct clk_ops	*ops;
 	struct clk_hw		*hw;
 	struct clk		*parent;
-	char			**parent_names;
+	const char		**parent_names;
 	struct clk		**parents;
 	u8			num_parents;
 	unsigned long		rate;