when outputing the description of a PCI device,
the quotation marks were missing

Signed-off-by: Christoph Ostarek <[email protected]>
(cherry picked from commit 23b5a75)

`spec.sh -v` would output `description` for PCI devices
twice. Once is enough though.

Whenever `add_pci_info` also `add_description` is called; as
`add_pci_info` already adds a description (in verbose mode),
there is no need to call `add_description` (which also only
adds a description if in verbose mode).
Therefore `add_description` can just be completely removed.

There is a call of `add_description` with the network interface name:
```
echo "$ETH" | sed -e 's#/net/.*'"${LABEL}" '##' -e 's#^.*/##'
```
but this one supposedly never worked, as `lspci -Ds` does not except
the network interface name as a parameter.

Signed-off-by: Christoph Ostarek <[email protected]>
(cherry picked from commit d6d4467)

if the iommu_group output is empty, then the key in
json was missing.
Fix this by not printing the iommu_group at all if no
iommu group can be found.

Signed-off-by: Christoph Ostarek <[email protected]>
(cherry picked from commit 849d3f4)

if the COM port is the last element of the IO bundles,
a superfluous comma was added at the end. This is an
error in json, so don't do this.

Signed-off-by: Christoph Ostarek <[email protected]>
(cherry picked from commit b7970e6)