lspci: better display of ranges behind a bridge

lspci: better display of ranges behind a bridge

When the range is non-empty, it is always printed together with
its size.

If it is empty, the output depends on the verbosity level chosen:

  - no verbosity: nothing is printed
  - -vvv: full range is printed
  - anything between: "none" is printed

Thanks to Harry Mallon and Bjorn Helgaas for inspiration.