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: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

drivers/mfd/tps65217.c

@@ -145,7 +145,7 @@ int tps65217_clear_bits(struct tps65217 *tps, unsigned int reg,
 }
 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,