motion: disable autotools host optimization

The motion autotools script helpfully detects the host
Microprocessors intr set and optimizes for it.
Disabling this feature causes autotools to use the
target parameters passed by BR instead.

Signed-off-by: Ray Kinsella <ray.kinsella@intel.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>