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/drivers/char/mwave/README b/drivers/char/mwave/README
index 70f8d19..480251f 100644
--- a/drivers/char/mwave/README
+++ b/drivers/char/mwave/README
@@ -41,10 +41,7 @@
 Accessing the driver
 --------------------
 
-You must also create a node for the driver.  Without devfs:
+You must also create a node for the driver:
   mkdir -p /dev/modems
   mknod --mode=660 /dev/modems/mwave c 10 219
-With devfs:
-  mkdir -p /dev/modems
-  ln -s ../misc/mwave /dev/modems/mwave