Enable using pre-fetched qcbor dependency

Modify Cmake scripts to enable using pre-fetched QCBOR source code
in the build. This is needed to support recent versions of yocto
where fetching of all dependencies is mandatory to be controlled
by yocto.

Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
13 files changed