optee: refactor into .inc files

To reduce code duplication, .inc files are used to hold common parts
of recipes, allowing .bb files to only specify things specific to that
recipe version.

Changed-Id: 740e6c9d36a957e2988f3599dd830c745f240beb
Signed-off-by: Brett Warren <brett.warren@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>