build: process dependencies before main build check

build: process dependencies before main build check

If we want to add support for turning off components because of missing
dependencies, then we need to check for those dependencies before we
make a determination as to whether a component should be built or not,
assuming that the component says it should be built.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>