CREDITS: correct Mikael Pettersson's URL

New URL due to local reorganization.
diff --git a/CREDITS b/CREDITS
index 550bb2b..b90b4ca 100644
--- a/CREDITS
+++ b/CREDITS
@@ -2702,7 +2702,7 @@
 
 N: Mikael Pettersson
 E: mikpe@it.uu.se
-W: http://www.csd.uu.se/~mikpe/
+W: http://user.it.uu.se/~mikpe/linux/
 D: Miscellaneous fixes
 
 N: Reed H. Petty