hwmon: jc42 depends on I2C

jc42 uses i2c interfaces, so it should depend on I2C.

drivers/hwmon/jc42.c:426: error: implicit declaration of function 'i2c_check_functionality'
drivers/hwmon/jc42.c:521: error: implicit declaration of function 'i2c_smbus_read_word_data'
drivers/hwmon/jc42.c:529: error: implicit declaration of function 'i2c_smbus_write_word_data'
drivers/hwmon/jc42.c:580: error: implicit declaration of function 'i2c_add_driver'
drivers/hwmon/jc42.c:585: error: implicit declaration of function 'i2c_del_driver'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>