lspci: Print names of capabilities even if we can't decode the rest

lspci: Print names of capabilities even if we can't decode the rest

We don't have decoders for many new capabilities, so we currently print
just the capability ID, e.g.,

  Capabilities: [220 v1] Extended Capability ID 0x19

Print the names, even if we don't yet know how to decode the contents,
e.g.,

  Capabilities: [220 v1] Secondary PCI Express <?>

The capability IDs are taken from the PCI Code and ID Assignment spec,
r1.10.  The #defines are named to match those in Linux when possible.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>