A ULP session will contain all the resources needed to support
rte flow offloads. A session is initialized as part of rte_eth_device
start. A DPDK application can have multiple interfaces which
means rte_eth_device start will be called for each of these devices.
ULP session manager will make sure that a single ULP session is only
initialized once. Apart from this, it also initializes MARK database,
EEM table & flow database. ULP session manager also manages a list of
all opened ULP sessions.
This patch adds support for cleaning up resources initialized for ULP
sessions.