xen: add kconfig menu

Currently the xen support drivers are displayed in the main Device Drivers
menu of the config tools instead of in their own sub-menu, so move them to
their own sub-menu, like the rest of the driver world uses.

This keeps the main Device Drivers menu from becoming messy.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/xen/Kconfig

+menu "Xen driver support"
+	depends on XEN
+
 config XEN_BALLOON
 	bool "Xen memory balloon driver"
-	depends on XEN
 	default y
 	help
 	  The balloon driver allows the Xen domain to request more memory from
@@ -20,7 +22,6 @@ config XEN_SCRUB_PAGES
 
 config XEN_DEV_EVTCHN
 	tristate "Xen /dev/xen/evtchn device"
-	depends on XEN
 	default y
 	help
 	  The evtchn driver allows a userspace process to triger event
@@ -30,7 +31,6 @@ config XEN_DEV_EVTCHN
 
 config XENFS
 	tristate "Xen filesystem"
-	depends on XEN
 	default y
 	help
 	  The xen filesystem provides a way for domains to share
@@ -53,7 +53,7 @@ config XEN_COMPAT_XENFS
 
 config XEN_SYS_HYPERVISOR
        bool "Create xen entries under /sys/hypervisor"
-       depends on XEN && SYSFS
+       depends on SYSFS
        select SYS_HYPERVISOR
        default y
        help
@@ -61,3 +61,5 @@ config XEN_SYS_HYPERVISOR
 	 hypervisor environment.  When running native or in another
 	 virtual environment, /sys/hypervisor will still be present,
 	 but will have no xen contents.
+
+endmenu