Update README to fix an error

Signed-off-by: Paul Mackerras <[email protected]>

Author: paulusmack

README

@@ -181,7 +181,7 @@ Copyrights:
 All of the code can be freely used and redistributed.  The individual
 source files each have their own copyright and permission notice.
 Pppd, pppstats and pppdump are under BSD-style notices.  Some of the
-pppd plugins are GPL'd.  Chat is public domain.
+pppd plugins are GPL'd.  Chat has an MIT licence notice.
 
 
 Distribution: