vlib: linux: fix wrong iommu_group value issue when using dpdk-plugin

vlib: linux: fix wrong iommu_group value issue when using dpdk-plugin

When VPP work with dpdk-plugin, linux_vfio_main_t->container_fd is always -1
since it never have chance to run open("/dev/vfio/vfio") to get the fd.

But this lead to a potential issue of VPP, that is, when start VPP without
uio-driver field setup in /etc/vpp/startup.conf, VPP will run to automatical
select uio driver in vlib_pci_bind_to_uio() and the function depend on
iommu_group value to decide to work on vfio or vfio-noiommu mode.

Since in vlib_pci_get_device_info() have the condition container_fd != -1,
so the iommu_group value will be always -1 at this scenario, this caused
that VPP mistake to run with vfio-noiommu driver on intel_iommu=on state.

Actually in order to get iommu_group and iommu_group/name value, no need to
depend on linux_vfio_main_t->container_fd value, so the fix remove the
condition lvm->container_fd != -1, then it can get the correct iommu_group
value.

Type: fix

Change-Id: I3f162fc4971b9a2b8717205f8f3b52e30c5e5b69
Signed-off-by: Yulong Pei <yulong.pei@intel.com>