regulator: ltc3589: Constify ltc3589_reg_defaults

ltc3589_reg_defaults[] is not modified after initialized, so make it const.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/ltc3589.c

@@ -378,7 +378,7 @@ static bool ltc3589_volatile_reg(struct device *dev, unsigned int reg)
 	return false;
 }
 
-static struct reg_default ltc3589_reg_defaults[] = {
+static const struct reg_default ltc3589_reg_defaults[] = {
 	{ LTC3589_SCR1,   0x00 },
 	{ LTC3589_OVEN,   0x00 },
 	{ LTC3589_SCR2,   0x00 },