config: Machanism to share files between host and FVP
Introduce "SHARE" rtvar for ns-preload.yaml, ns-edk2.yaml (and all derived configs, including cca-3world.yaml, ffa-tftf.yaml, etc). It defaults to empty, but when specified on the "run" command line, indicates a host directory to share into the FVP.
The directory is shared using 9p, and must be mounted inside the FVP with (e.g.):
mkdir /share
mount -t 9p -o trans=virtio,version=9p2000.L FM /share
Signed-off-by: Ryan Roberts ryan.roberts@arm.com