vhost: drop vringh dependency

vringh isn't used by vhost net or scsi - it's used
by CAIF only at the moment. Drop the dependency.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/Makefile

@@ -139,6 +139,7 @@ obj-$(CONFIG_OF)		+= of/
 obj-$(CONFIG_SSB)		+= ssb/
 obj-$(CONFIG_BCMA)		+= bcma/
 obj-$(CONFIG_VHOST_RING)	+= vhost/
+obj-$(CONFIG_VHOST)		+= vhost/
 obj-$(CONFIG_VLYNQ)		+= vlynq/
 obj-$(CONFIG_STAGING)		+= staging/
 obj-y				+= platform/