CREDITS: correct Mikael Pettersson's URL

New URL due to local reorganization.

CREDITS

@@ -2702,7 +2702,7 @@ S: Canada K2P 0X8
 
 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