set-override for a device with vfio-pci attempts to dynamically add the
device by writing to new_id.

This leads to an "echo: write error: File exists" error message when
set-override is used more than once for the same device.

This is because duplicate writes to new_id for the same device are not
allowed since Linux kernel (v5.11) commit:
3853f9123c18 ("PCI: Avoid duplicate IDs in driver dynamic IDs list")

Squash the error message.

Fixes: 9fb114e7

 ("Fix device driver binding issue after re-enumeration")
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>