lpm: fix overflow issue
lpm: fix overflow issue

LPM table overflow may occur if table is full and added rule has
the biggest depth that already have some rules.

Signed-off-by: Igor Ryzhov <b03ec72ab44ca5800dd91e71c433a63ed86c5f25@nfware.com>
Acked-by: Bruce Richardson <66b9e8e8fbd5e9f41f91b0af050876182ce9d0e4@intel.com>

phermansson/dpdk,phermansson/dpdk,phermansson/dpdk,phermansson/dpdk