ixgbe: fix secondary process start

ixgbe: fix secondary process start

EAL:   probe driver: 8086:10fb rte_ixgbe_pmd
EAL:   PCI memory mapped at 0x7f18c2a00000
EAL:   PCI memory mapped at 0x7f18c2a80000
Segmentation fault (core dumped)

This is introduced by commit: 46bc9d75
	ixgbe: fix multi-process support
When start primary process with command line:
./app/test/test -n 1 -c ffff -m 64
then start the second one:
./app/test/test -n 1 --proc-type=secondary --file-prefix=rte
This segment-fault will occur.

Root cause is test app on primary process only starts device, but
the queue need initialized by manually command line.
So the tx queue is still NULL when secondary process startup.

Reported-by: Yong Liu <yong.liu@intel.com>
Signed-off-by: Michael Qiu <michael.qiu@intel.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>