mondrianwifi: Add Torch using the camera interface

Enabling Torch mode via the sysfs interface causes the tablet to
reboot.  I suspect that the flash is drawing too much power and
that going via the camera interface is required to ensure that
sufficient power is being provided.

Either way, using the camera interface seems to work.

Change-Id: Ibcf0e70eed2ffe5b7347162c745bffc35cf1e60a