yocto/[baremetal,virtualization]: Add openvswitch support

Add openvswitch package to baremetal and virtualization profiles
and add Kconfig needed to build the openvswitch kernel module.

iptables is a package needed by openvswitch.

Add 'openvswitch' to the dictionary.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>