power: supply: bq27xxx: Add chip data memory read/write support

Add these to enable read/write of chip data memory RAM/NVM/flash:
  bq27xxx_battery_seal()
  bq27xxx_battery_unseal()
  bq27xxx_battery_set_cfgupdate()
  bq27xxx_battery_soft_reset()
  bq27xxx_battery_read_dm_block()
  bq27xxx_battery_write_dm_block()
  bq27xxx_battery_checksum_dm_block()
Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Signed-off-by: Liam Breck <kernel@networkimprov.net>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

include/linux/power/bq27xxx_battery.h

@@ -64,6 +64,7 @@ struct bq27xxx_device_info {
 	int id;
 	enum bq27xxx_chip chip;
 	const char *name;
+	u32 unseal_key;
 	struct bq27xxx_access_methods bus;
 	struct bq27xxx_reg_cache cache;
 	int charge_design_full;