ia64: Remove dev->archdata.iommu pointer

There are no users left, all drivers have been converted to use the
per-device private pointer offered by IOMMU core.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20200625130836.1916-11-joro@8bytes.org

arch/ia64/include/asm/device.h

@@ -6,9 +6,6 @@
 #define _ASM_IA64_DEVICE_H
 
 struct dev_archdata {
-#ifdef CONFIG_IOMMU_API
-	void *iommu; /* hook for IOMMU specific extension */
-#endif
 };
 
 struct pdev_archdata {