wigig_sensing: make change_mode ioctl more robust

Prevent state changes during DRI handling, which may cause the driver to
get out of synchronization. Prevent data read from user space and from
kernel space during change_mode processing.

Change-Id: I2ee277c8894996119d13acbe87a5163e4064923c
Signed-off-by: Gidon Studinski <gidons@codeaurora.org>