Documentation: PCI: pci.rst: drop doubled words

Drop the doubled word "when".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Link: https://lore.kernel.org/r/20200703212156.30453-5-rdunlap@infradead.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>