vfio: Select iommufd

vfio core calls iommufd symbol, needs to select explicitly. Currently
iommufd compat mode only available for vfio iommu type1, so if type1
selected, iommufd should also be selected.

Signed-off-by: Liu Yi L <yi.l.liu@intel.com>

drivers/vfio/Kconfig

@@ -2,6 +2,7 @@
 menuconfig VFIO
 	tristate "VFIO Non-Privileged userspace driver framework"
 	select IOMMU_API
+	select IOMMUFD if MMU && (X86 || S390 || ARM || ARM64)
 	select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64)
 	help
 	  VFIO provides a framework for secure userspace device drivers.