remove mentionings of devfs in documentation

Now that devfs is removed, there's no longer any need to document how to
do this or that with devfs.

This patch includes some improvements by Joe Perches.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/input/input.txt b/Documentation/input/input.txt
index 550ef9a..ac22f63 100644
--- a/Documentation/input/input.txt
+++ b/Documentation/input/input.txt
@@ -68,8 +68,8 @@
 
 	crw-r--r--   1 root     root      13,  63 Mar 28 22:45 mice
 
-  This device has to be created, unless you use devfs, in which case it's
-created automatically. The commands to do create it by hand are:
+  This device has to be created.
+  The commands to create it by hand are:
 
 	cd /dev
 	mkdir input