Input: mma8450 - add missing i2c_set_clientdata() in mma8450_probe()

Add missing i2c_set_clientdata() in mma8450_probe(), otherwise
calling i2c_get_clientdata() in mma8450_remove() returns NULL.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>