utils/spidev_test: side-step build-system woes

utils/spidev_test: side-step build-system woes

The spidev_test is build in phase2 even though it should be disabled.
My best guess is that we hit the same issue that I had with nu801.
The build-system thinks it's a tool that is necessary for
building the kernel.

In this case, the same fix (adding a dependency on the presence of
the module) could work in this case as well?

Fixes: bdaaf66e28bd ("utils/spidev_test: build package directly from Linux")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>