igb_uio: fix IRQ disable on recent kernels

igb_uio: fix IRQ disable on recent kernels

igb_uio already allocates irqs using pci_alloc_irq_vectors on
recent kernels >= 4.8. The interrupt disable code was not
using the corresponding pci_free_irq_vectors, but the also
deprecated pci_disable_msix, before this fix.

Fixes: 99bb58f3adc7 ("igb_uio: switch to new irq function for MSI-X")
Cc: stable@dpdk.org
Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>