Intel SkyLake-E was successfully tested for p2pdma transactions spanning
over a host bridge and PCI bridge with IOMMU on.  Add it to the whitelist.

Link: https://lore.kernel.org/r/1575669165-31697-1-git-send-email-abaloyan@gigaio.comSigned-off-by: Armen Baloyan <abaloyan@gigaio.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>