xen: remove redundant 'default n' from Kconfig

'default n' is the default value for any bool or tristate Kconfig
setting so there is no need to write it explicitly.

Also since commit f467c564 ("kconfig: only write '# CONFIG_FOO
is not set' for visible symbols") the Kconfig behavior is the same
regardless of 'default n' being present or not:

    ...
    One side effect of (and the main motivation for) this change is making
    the following two definitions behave exactly the same:

        config FOO
                bool

        config FOO
                bool
                default n

    With this change, neither of these will generate a
    '# CONFIG_FOO is not set' line (assuming FOO isn't selected/implied).
    That might make it clearer to people that a bare 'default n' is
    redundant.
    ...
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/Kconfig

@@ -12,7 +12,6 @@ config XEN_BALLOON
 config XEN_SELFBALLOONING
 	bool "Dynamically self-balloon kernel memory to target"
 	depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
-	default n
 	help
 	  Self-ballooning dynamically balloons available kernel memory driven
 	  by the current usage of anonymous memory ("committed AS") and
@@ -27,7 +26,6 @@ config XEN_SELFBALLOONING
 
 config XEN_BALLOON_MEMORY_HOTPLUG
 	bool "Memory hotplug support for Xen balloon driver"
-	default n
 	depends on XEN_BALLOON && MEMORY_HOTPLUG
 	help
 	  Memory hotplug support for Xen balloon driver allows expanding memory
@@ -226,7 +224,6 @@ config XEN_PCIDEV_BACKEND
 config XEN_PVCALLS_FRONTEND
 	tristate "XEN PV Calls frontend driver"
 	depends on INET && XEN
-	default n
 	select XEN_XENBUS_FRONTEND
 	help
 	  Experimental frontend for the Xen PV Calls protocol
@@ -237,7 +234,6 @@ config XEN_PVCALLS_FRONTEND
 config XEN_PVCALLS_BACKEND
 	bool "XEN PV Calls backend driver"
 	depends on INET && XEN && XEN_BACKEND
-	default n
 	help
 	  Experimental backend for the Xen PV Calls protocol
 	  (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
@@ -263,7 +259,6 @@ config XEN_PRIVCMD
 config XEN_STUB
 	bool "Xen stub drivers"
 	depends on XEN && X86_64 && BROKEN
-	default n
 	help
 	  Allow kernel to install stub drivers, to reserve space for Xen drivers,
 	  i.e. memory hotplug and cpu hotplug, and to block native drivers loaded,
@@ -274,7 +269,6 @@ config XEN_STUB
 config XEN_ACPI_HOTPLUG_MEMORY
 	tristate "Xen ACPI memory hotplug"
 	depends on XEN_DOM0 && XEN_STUB && ACPI
-	default n
 	help
 	  This is Xen ACPI memory hotplug.
 
@@ -286,7 +280,6 @@ config XEN_ACPI_HOTPLUG_CPU
 	tristate "Xen ACPI cpu hotplug"
 	depends on XEN_DOM0 && XEN_STUB && ACPI
 	select ACPI_CONTAINER
-	default n
 	help
 	  Xen ACPI cpu enumerating and hotplugging
 
@@ -315,7 +308,6 @@ config XEN_ACPI_PROCESSOR
 config XEN_MCE_LOG
 	bool "Xen platform mcelog"
 	depends on XEN_DOM0 && X86_64 && X86_MCE
-	default n
 	help
 	  Allow kernel fetching MCE error from Xen platform and
 	  converting it into Linux mcelog format for mcelog tools