tests/qtest/libqos/igb: Set GPIE.Multiple_MSIX

GPIE.Multiple_MSIX is not set by default, and needs to be set to get
interrupts from multiple MSI-X vectors.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Jason Wang <jasowang@redhat.com>

tests/qtest/libqos/igb.c

@@ -114,6 +114,7 @@ static void igb_pci_start_hw(QOSGraphObject *obj)
     e1000e_macreg_write(&d->e1000e, E1000_RCTL, E1000_RCTL_EN);
 
     /* Enable all interrupts */
+    e1000e_macreg_write(&d->e1000e, E1000_GPIE,  E1000_GPIE_MSIX_MODE);
     e1000e_macreg_write(&d->e1000e, E1000_IMS,  0xFFFFFFFF);
     e1000e_macreg_write(&d->e1000e, E1000_EIMS, 0xFFFFFFFF);