ethdev: support multi-host in representor

ethdev: support multi-host in representor

The NIC can have multiple PCIe links and can be attached to the multiple
hosts, for example the same single NIC can be shared for multiple server
units in the rack. On each PCIe link NIC can provide multiple PFs and
VFs/SFs based on these ones. To provide the unambiguous identification
of the PCIe function the controller index is added. The full representor
identifier consists of three indices - controller index, PF index, and
VF or SF index (if any).

This patch introduces controller index to ethdev representor syntax,
examples:

[[c#]pf#]vf#: VF port representor/s, example: pf0vf1
[[c#]pf#]sf#: SF port representor/s, example: c1pf1sf[0-3]

c# is controller(host) ID/range in case of multi-host, optional.

For user application (e.g. OVS), PMD is responsible to interpret and
locate representor device based on controller ID, PF ID and VF/SF ID in
representor syntax.

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>