Some configuration options can not be tested properly with testpmd
because it automatically starts all ports. This makes it harder
to test driver handling of configuration options:
(for example rx_deferred_start).
Add new command line flag --disable-device-start which skips
the device start. The port can then be started manually later.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>