MAINTAINERS: add myself as lavd/xv maintainer

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

MAINTAINERS

@@ -317,6 +317,7 @@ libavdevice
   sdl                                   Stefano Sabatini
   v4l2.c                                Luca Abeni
   vfwcap.c                              Ramiro Polla
+  xv.c                                  Lukasz Marek
 
 libavfilter
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