app/test: fix multi-process when device is bound to uio

app/test: fix multi-process when device is bound to uio

Since commit a155d4301 "support link bonding device initialization",
EAL probes drivers to the PCI devices in rte_eal_init,
then PCI resources are mapped if a device
is bound to igb_uio driver, for instance.
Therefore, test app probes all the devices and multiprocess unit test
tries to map resources twice in the secondary processes, and test fails,
caused by RTE_PCI_DRV_NEEDED_MAPPING flag in dummy pci driver my_driver2.

Test is fixed by setting the driver flags to 0.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>