Fix toogle whether xenbus driver should be built as module or part of kernel.

The "select" statement in the Kconfig ensures that all other users
of the xenbus will have the same dependency.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
index cd50c00..b8e0424 100644
--- a/drivers/input/Kconfig
+++ b/drivers/input/Kconfig
@@ -153,6 +153,7 @@
 	tristate "Xen virtual keyboard and mouse support"
 	depends on XEN_FBDEV_FRONTEND
 	default y
+	select XEN_XENBUS_FRONTEND
 	help
 	  This driver implements the front-end of the Xen virtual
 	  keyboard and mouse device driver.  It communicates with a back-end