vfio: Fix build break when SPAPR_TCE_IOMMU=n

Currently the kconfig logic for VFIO_IOMMU_SPAPR_TCE and VFIO_SPAPR_EEH
is broken when SPAPR_TCE_IOMMU=n. Leading to:

warning: (VFIO) selects VFIO_IOMMU_SPAPR_TCE which has unmet direct dependencies (VFIO && SPAPR_TCE_IOMMU)
warning: (VFIO) selects VFIO_IOMMU_SPAPR_TCE which has unmet direct dependencies (VFIO && SPAPR_TCE_IOMMU)
drivers/vfio/vfio_iommu_spapr_tce.c:113:8: error: implicit declaration of function 'mm_iommu_find'

This stems from the fact that VFIO selects VFIO_IOMMU_SPAPR_TCE, and
although it has an if clause, the condition is not correct.

We could fix it by doing select VFIO_IOMMU_SPAPR_TCE if SPAPR_TCE_IOMMU,
but the cleaner fix is to drop the selects and tie VFIO_IOMMU_SPAPR_TCE
to the value of VFIO, and express the dependencies in only once place.

Do the same for VFIO_SPAPR_EEH.

The end result is that the values of VFIO_IOMMU_SPAPR_TCE and
VFIO_SPAPR_EEH follow the value of VFIO, except when SPAPR_TCE_IOMMU=n
and/or EEH=n. Which is exactly what we want to happen.

Signed-off-by: Michael Ellerman <[e-mail]>
Signed-off-by: Alex Williamson <[e-mail]>

drivers/vfio/Kconfig

···
 config VFIO_IOMMU_SPAPR_TCE
 	tristate
 	depends on VFIO && SPAPR_TCE_IOMMU
-	default n
+	default VFIO
 
 config VFIO_SPAPR_EEH
 	tristate
 	depends on EEH && VFIO_IOMMU_SPAPR_TCE
-	default n
+	default VFIO
 
 config VFIO_VIRQFD
 	tristate
···
 	tristate "VFIO Non-Privileged userspace driver framework"
 	depends on IOMMU_API
 	select VFIO_IOMMU_TYPE1 if (X86 || S390 || ARM_SMMU || ARM_SMMU_V3)
-	select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
-	select VFIO_SPAPR_EEH if (PPC_POWERNV || PPC_PSERIES)
 	select ANON_INODES
 	help
 	  VFIO provides a framework for secure userspace device drivers.