rtc: ds1307: fix regmap config

Current max_register setting breaks reading nvram on certain chips and
also reading the standard registers on RX8130 where register map starts
at 0x10.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Fixes: 11e5890 "rtc: ds1307: convert driver to regmap"
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-ds1307.c

@@ -1301,7 +1301,6 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
 static const struct regmap_config regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.max_register = 0x12,
 };
 
 static int ds1307_probe(struct i2c_client *client,