[qca-nss-ecm] Add multipath support

- Changed the way how the interface hierarchies are constructed.
  The from/to interfaces are obtained from the skb's route field
  and passed to the hierarchy constuct and the node establish functions
  instead of doing route lookups using the ip addresses to find the
  interfaces. To achieve this the new interface hierarchy construct and
  node establish functions are imlemented.
- Implemented new mac address lookup functions whcih do not require
  route lookups.
- Implemented new ipv4 and ipv6 gateway find functions which finds
  the gateway IP address to reach to a destination IP address.
- Keep the old APIs for the multicast feature. It is not done yet.

Change-Id: Ib81ad37d5b60af490b93884448669ad2178b9ad2
Signed-off-by: Murat Sezgin <msezgin@codeaurora.org>
23 files changed