xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
they don't use the xen frame buffer frontend. For this case it doesn't
make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 7b46781..8f675ae 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -558,7 +558,7 @@
 
 config INPUT_XEN_KBDDEV_FRONTEND
 	tristate "Xen virtual keyboard and mouse support"
-	depends on XEN_FBDEV_FRONTEND
+	depends on XEN
 	default y
 	select XEN_XENBUS_FRONTEND
 	help