i2c: i801: Use driver name constant instead of function dev_driver_string

We are the driver, so we can use the driver name directly instead of
retrieving it by calling dev_driver_string().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>