vfio: IOMMU_API should be selected

As IOMMU_API is a kconfig without a description (eg does not show in the
menu) the correct operator is select not 'depends on'. Using 'depends on'
for this kind of symbol means VFIO is not selectable unless some other
random kconfig has already enabled IOMMU_API for it.

Fixes: cba3345 ("vfio: VFIO core")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <1-v1-df057e0f92c3+91-vfio_arm_compile_test_jgg@nvidia.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Kconfig

@@ -21,7 +21,7 @@ config VFIO_VIRQFD
 
 menuconfig VFIO
 	tristate "VFIO Non-Privileged userspace driver framework"
-	depends on IOMMU_API
+	select IOMMU_API
 	select VFIO_IOMMU_TYPE1 if (X86 || S390 || ARM || ARM64)
 	help
 	  VFIO provides a framework for secure userspace device drivers.