dmatrix/reedsol: updated to reflect addtional re-licensing under

BSD-3-clause of the contributions of Andrews & Arnold Ltd. -
  many thanks to the Rev Adrian Kennard; corrected "reedsol"
  copyright; removed Stefan Schmidt copyright as only difference
  from originals is whitespace/formatting
  (ticket #357, props stefan6419846)

backend/dmatrix.c

@@ -9,7 +9,8 @@
         with help from Cliff Hones on the RS coding
 
         Copyright (c) 2004 Adrian Kennard, Andrews & Arnold Ltd
-        Copyright (c) 2006 Stefan Schmidt <stefan@datenfreihafen.org>
+        which had been re-licensed additionally under BSD-3-clause:
+        https://codeberg.org/RevK/Datamatrix/src/branch/master/LICENSE
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions

backend/reedsol.c

@@ -1,6 +1,9 @@
 /*
     This is a simple Reed-Solomon encoder
-    Copyright (C) Cliff Hones 2004
+    Copyright (C) 2004 Andrews & Arnold Ltd
+    Written by Cliff Hones
+    which had been re-licensed additionally under BSD-3-clause:
+    https://codeberg.org/RevK/Reedsol/src/branch/master/LICENSE
 */
 /*
     libzint - the open source barcode library

backend/reedsol.h

@@ -1,6 +1,10 @@
 /*
     This is a simple Reed-Solomon encoder
     (C) Cliff Hones 2004
+    Copyright (C) 2004 Andrews & Arnold Ltd
+    Written by Cliff Hones
+    which had been re-licensed additionally under BSD-3-clause:
+    https://codeberg.org/RevK/Reedsol/src/branch/master/LICENSE
 */
 /*
     libzint - the open source barcode library