CI: use bitbake+oe-core instead of poky
Moving forwards, it's expected that the poky repository will no longer be
updated as the integration of bitbake-setup means that users are
encouraged to use bitbake+oe-core separately instead.
We also need to fetch meta-yocto as our CI is currently explicitly based
on the poky distribution.
This is effectively a no-op change, as poky is simply these component
repositories glued into a single repository for convenience.
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>
Ross Burton