Add Mateusz Kubica to the credits.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16266 a1c6a512-1295-4272-9138-f99709370657
diff --git a/docs/CREDITS b/docs/CREDITS
index 24d58e4..7c95ab8 100644
--- a/docs/CREDITS
+++ b/docs/CREDITS
@@ -367,6 +367,7 @@
 George Tamplaru
 Apoorva Mahajan
 Vuong Minh Hiep
+Mateusz Kubica
 
 The libmad team
 The wavpack team