i2c: remove CONFIG_HOTPLUG ifdefs

CONFIG_HOTPLUG is going away as an option, cleanup CONFIG_HOTPLUG
ifdefs in i2c files.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>