pci-arbiter TODO: remove items

[Joan Lledó]

Hello,

In the TODO of the pci-arbiter there are some items we could probably remove:

- add "--pci 00:1f.3" option to easily specify a PCI device instead of having to
  use --bus, --dev, and --func.

This one can be removed since it's already done.


- memset + snprintf looks dubious

I'm not sure what this one means, but I think it's resolved as well, since I
couldn't find any call to memset and snprintf close to each other in the code.

Anyway, during the code preview to find memset and snprintf calls I found a
useless call to memset at [1]. TBH, I don't remember why I wrote that, but it
doesn't seem to make sense, since it's setting to zero only the first directory
entry the loop creates, and is not doing it for the rest. I wrote a little patch
to set to zero all directory entries before creating them.

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[1] http://git.savannah.gnu.org/cgit/hurd/hurd.git/tree/pci-arbiter/pcifs.c#n202