input: sensors: add bma2x2 support schedule data poll on idle CPU

In order to boost sensor data polling/processing performance
for bma2x2 accel sensors on various platforms, use kthread
instead of workqueue and set_wake_up_idle() for high frequency
streaming usecase.

Change-Id: Idd98cfae7550b5180c5ad48094fdd65d5e092aea
Signed-off-by: Daqing Chen <chendaqing@codeaurora.org>
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>