For privieleged containers, all host devices are passed to
container. We have done work in crio and containerd to define a
scope of privileged in Kata to prevent this from happening.
Add this as the default as this falls under a best practice to follow
with Kata.
Note that if this flag has been already defined, then this change
does not override it.
Fixes#582
Signed-off-by: Archana Shinde <archana.m.shinde@intel.com>