mfd: tps65217: Constify struct regmap_config

The regmap_config struct may be const because it is not modified by the
driver and regmap_init() accepts pointer to const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/tps65217.c b/drivers/mfd/tps65217.c
index 80a919a..7d1cfc1 100644
--- a/drivers/mfd/tps65217.c
+++ b/drivers/mfd/tps65217.c
@@ -145,7 +145,7 @@
 }
 EXPORT_SYMBOL_GPL(tps65217_clear_bits);
 
-static struct regmap_config tps65217_regmap_config = {
+static const struct regmap_config tps65217_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,