MAINTAINERS: new ffplay maintainer

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit cffd20b90e)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

MAINTAINERS

@@ -19,7 +19,7 @@ ffmpeg:
   ffmpeg.c                              Michael Niedermayer
 
 ffplay:
-  ffplay.c                              Michael Niedermayer
+  ffplay.c                              Marton Balint
 
 ffprobe:
   ffprobe.c                             Stefano Sabatini