PCI: thunder-pem: Use Cavium assigned hardware ID for ThunderX host controller

"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+

drivers/pci/host/pci-thunder-pem.c

@@ -346,7 +346,7 @@ static int thunder_pem_acpi_init(struct pci_config_window *cfg)
 	if (!res_pem)
 		return -ENOMEM;
 
-	ret = acpi_get_rc_resources(dev, "THRX0002", root->segment, res_pem);
+	ret = acpi_get_rc_resources(dev, "CAVA02B", root->segment, res_pem);
 	if (ret) {
 		dev_err(dev, "can't get rc base address\n");
 		return ret;