vfio: generalize non PCI-specific functions

vfio: generalize non PCI-specific functions

The pci_vfio_set_iommu_type is not PCI-specific and it is a private function
of the eal_pci_vfio.c. We just rename the function and make it available even
for non-PCI devices.

The pci_vfio_has_supported_extensions is not PCI-specific and it is a private
function of the eal_pci_vfio.c. We just rename the function and make it
available even for non-PCI devices.

The pci_vfio_get_container_fd is not PCI-specific. Move the implementation to
the eal_vfio.c as vfio_get_container_fd. No other code seems to call this
function.

Generalize the pci_vfio_get_group_no to not be PCI-specific. Move the general
implementation to the eal_vfio.c as vfio_get_group_no and leave the original
pci_vfio_get_group_no being a wrapper around this to preserve compilation
issues. The pci_vfio_get_group_no function will be removed later.

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>