If we have multiple network interfaces and we want to send
a IPv4 network packet to certain destination, then this new
helper can be used to figure out what network interface to use.
Note that this commit only adds support to select the correct network
interface according to destination IPv4 address. This does not enable
any automatic routing to happen.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
