add a video group for lemote webcam support

package/mplayer/files/mplayer.postinst

@@ -0,0 +1,4 @@
+#!/bin/sh
+. $IPKG_INSTROOT/etc/functions.sh
+gid=$(get_next_gid)
+add_group video $gid

target/lemote/files/etc/mdev.conf

@@ -13,4 +13,5 @@ timer root:audio 660 >snd/timer
 controlC0 root:audio 660 >snd/controlC0
 pcmC0D0c root:audio 660 >snd/pcmC0D0c
 pcmC0D0p root:audio 660 >snd/pcmC0D0p
+video0 root:video 660
 .* 0:0 644 @/lib/mdev/init