nfp: parse vNIC TLV capabilities at alloc time

In certain cases initialization logic which follows allocation of
the vNIC structure may want to validate the capabilities of that vNIC.
This is easy before vNIC is initialized for normal capabilities which
are at fixed offsets in control memory, easy to locate and read, but
poses a challenge if the capabilities are in form of TLVs.  Parse
the TLVs early on so other code can just access parsed info, instead
of having to do the parsing by itself.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>