Add verification of FIT_DESC to the existing test for kernel-fitimage.
(From OE-Core rev: 1d75a67efe968f1d9161b64e2b7b2d3cf482c968)
Signed-off-by: Paul Eggleton <paul.eggleton@microsoft.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>