mov: Add missing terminator to mov_ch_layout_map_1ch.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: Libav-stable@libav.org

libavformat/mov_chan.c

@@ -155,6 +155,7 @@ static const struct MovChannelLayoutMap mov_ch_layout_map_misc[] = {
 
 static const struct MovChannelLayoutMap mov_ch_layout_map_1ch[] = {
     { MOV_CH_LAYOUT_MONO,               AV_CH_LAYOUT_MONO }, // C
+    { 0, 0 },
 };
 
 static const struct MovChannelLayoutMap mov_ch_layout_map_2ch[] = {