netdev-dpdk: Refactor dpdk_class_init()
The following changes were made:
- Since we have two dpdk classes, we should split the initial operations needed
by both classes from the initialization needed by each class.
- The dpdk_ring class does not need an initialization function: it has been
removed. This also prevents many testcase from failing, because
dpdk_ring_class_init() was printing an unexpected log message
(OVS_VSWITCHD_START at tests/ofproto-macros.at:54 check for a specific set of
startup log messages)
- If the user doesn't pass the --dpdk option we do not register the dpdk*
classes
- Do not call VLOG_ERR if there are 0 dpdk ethernet device. OVS can now be used
with dpdk_ring devices.
Signed-off-by: Daniele Di Proietto <ddiproietto@vmware.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>