um: clean Kconfig up a bit

* kill duplicates with drivers/char/Kconfig
* take watchdog one into drivers/watchdog/Kconfig
* take mmapper to arch/um/Kconfig.um
* rename Kconfig.char menu to "UML Character Devices"

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 86b0735..340b2b3 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1174,6 +1174,10 @@
 	  by Xen 4.0 and newer.  The watchdog timeout period is normally one
 	  minute but can be changed with a boot-time parameter.
 
+config UML_WATCHDOG
+	tristate "UML watchdog"
+	depends on UML
+
 #
 # ISA-based Watchdog Cards
 #