debugfs: introduce stub for debugfs_create_size_t() when DEBUG_FS=n

Toralf Förster <toralf.foerster@gmx.de> reported a build failure in
the WiMAX stack when CONFIG_DEBUG_FS=n

http://linuxwimax.org/pipermail/wimax/2009-January/000449.html

This is due to debugfs_create_size_t() missing an stub that returns
-ENODEV when the DEBUGFS subsystem is not configured in (like the rest
of the debugfs API).

This patch adds said stub.
Reported-by: NToralf Förster <toralf.foerster@gmx.de>
Signed-off-by: NInaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

include/linux/debugfs.h

@@ -162,6 +162,13 @@ static inline struct dentry *debugfs_create_x32(const char *name, mode_t mode,
 	return ERR_PTR(-ENODEV);
 }
 
+struct dentry *debugfs_create_size_t(const char *name, mode_t mode,
+				     struct dentry *parent,
+				     size_t *value)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline struct dentry *debugfs_create_bool(const char *name, mode_t mode,
 						 struct dentry *parent,
 						 u32 *value)