input: sensors: add interrupt mode support for MPU6050

Add new function to configure interrupt register that allow sensor
to work on interrupt mode. When interrupt mode is enabled, sensor
can work at background and allow AP processor to sleep, it will
issue interrupt to wakeup AP processor until any preset condition is
meet.

Change-Id: I3e535af12ca200b744c9ee7a3f90a79f23640bd1
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>