use Kostyas full name in copyrights

This fixes 2 files that where not part of the original change
See: de421b20Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/arm/int_neon.S

 /*
  * ARM NEON optimised integer operations
- * Copyright (c) 2009 Kostya Shishkov
+ * Copyright (c) 2009 Konstantin Shishkov
  *
  * This file is part of FFmpeg.
  *

libavformat/wvenc.c

 /*
  * WavPack muxer
- * Copyright (c) 2013 Kostya Shishkov <kostya.shishkov@gmail.com>
+ * Copyright (c) 2013 Konstantin Shishkov <kostya.shishkov@gmail.com>
  * Copyright (c) 2012 Paul B Mahol
  *
  * This file is part of FFmpeg.