vfio: Use select for eventfd

If VFIO_VIRQFD is required then turn on eventfd automatically.
The majority of kconfig users of the EVENTFD use select not depends on.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20210826103912.128972-12-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Kconfig

@@ -16,7 +16,8 @@ config VFIO_SPAPR_EEH
 
 config VFIO_VIRQFD
 	tristate
-	depends on VFIO && EVENTFD
+	depends on VFIO
+	select EVENTFD
 	default n
 
 menuconfig VFIO

drivers/vfio/fsl-mc/Kconfig

@@ -1,6 +1,7 @@
 config VFIO_FSL_MC
 	tristate "VFIO support for QorIQ DPAA2 fsl-mc bus devices"
-	depends on VFIO && FSL_MC_BUS && EVENTFD
+	depends on VFIO && FSL_MC_BUS
+	select EVENTFD
 	help
 	  Driver to enable support for the VFIO QorIQ DPAA2 fsl-mc
 	  (Management Complex) devices. This is required to passthrough

drivers/vfio/pci/Kconfig

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config VFIO_PCI
 	tristate "VFIO support for PCI devices"
-	depends on VFIO && PCI && EVENTFD
+	depends on VFIO && PCI
 	depends on MMU
 	select VFIO_VIRQFD
 	select IRQ_BYPASS_MANAGER

drivers/vfio/platform/Kconfig

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config VFIO_PLATFORM
 	tristate "VFIO support for platform devices"
-	depends on VFIO && EVENTFD && (ARM || ARM64 || COMPILE_TEST)
+	depends on VFIO && (ARM || ARM64 || COMPILE_TEST)
 	select VFIO_VIRQFD
 	help
 	  Support for platform devices with VFIO. This is required to make