eal: force IOVA to a particular mode

eal: force IOVA to a particular mode

This patch uses EAL option "--iova-mode" to force the IOVA mode to a
particular value. There exists virtual devices that are not directly
attached to the PCI bus, and therefore the auto detection of the IOVA
mode based on probing the PCI bus and IOMMU configuration may not
report the required addressing mode. Using the EAL option permits the
mode to be explicitly configured in this scenario.

Signed-off-by: Eric Zhang <eric.zhang@windriver.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Marko Kovacevic <marko.kovacevic@intel.com>