ACPI/IORT: Remove the unused __get_pci_rid()

Since commit bc8648d4 ("ACPI/IORT: Handle PCI aliases properly for
IOMMUs"), __get_pci_rid() has become actually unused and can be removed.
Signed-off-by: NZenghui Yu <yuzenghui@huawei.com>
Acked-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NHanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20200509093430.1983-1-yuzenghui@huawei.comSigned-off-by: NWill Deacon <will@kernel.org>

drivers/acpi/arm64/iort.c

@@ -772,15 +772,6 @@ void acpi_configure_pmsi_domain(struct device *dev)
 		dev_set_msi_domain(dev, msi_domain);
 }
 
-static int __maybe_unused __get_pci_rid(struct pci_dev *pdev, u16 alias,
-					void *data)
-{
-	u32 *rid = data;
-
-	*rid = alias;
-	return 0;
-}
-
 #ifdef CONFIG_IOMMU_API
 static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
 {