fsnotify: use def_bool in kconfig instead of letting the user choose

fsnotify doens't give the user anything.  If someone chooses inotify or
dnotify it should build fsnotify, if they don't select one it shouldn't be
built.  This patch changes fsnotify to be a def_bool=n and makes everything
else select it.  Also fixes the issue people complained about on lwn where
gdm hung because they didn't have inotify and they didn't get the inotify
build option.....
Signed-off-by: NEric Paris <eparis@redhat.com>

fs/notify/Kconfig

 config FSNOTIFY
-	bool "Filesystem notification backend"
-	default y
-	---help---
-	   fsnotify is a backend for filesystem notification.  fsnotify does
-	   not provide any userspace interface but does provide the basis
-	   needed for other notification schemes such as dnotify, inotify,
-	   and fanotify.
-
-	   Say Y here to enable fsnotify suport.
-
-	   If unsure, say Y.
+	def_bool n
 
 source "fs/notify/dnotify/Kconfig"
 source "fs/notify/inotify/Kconfig"

fs/notify/dnotify/Kconfig

 config DNOTIFY
 	bool "Dnotify support"
-	depends on FSNOTIFY
+	select FSNOTIFY
 	default y
 	help
 	  Dnotify is a directory-based per-fd file change notification system

fs/notify/inotify/Kconfig

@@ -15,7 +15,7 @@ config INOTIFY
 
 config INOTIFY_USER
 	bool "Inotify support for userspace"
-	depends on FSNOTIFY
+	select FSNOTIFY
 	default y
 	---help---
 	  Say Y here to enable inotify support for userspace, including the