"CAV" is the only PNP/ACPI hardware ID vendor prefix assigned to Cavium so
fix this as it should be from day one.

Fixes: 44f22bd9 ("PCI: Add MCFG quirks for Cavium ThunderX pass2.x host controller")
Tested-by: NRobert Richter <rrichter@cavium.com>
Signed-off-by: NTomasz Nowicki <tn@semihalf.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRobert Richter <rrichter@cavium.com>
CC: stable@vger.kernel.org	# v4.10+