bfin: unbreak compilation

Added a missing header file.
movenc: Simplify code by using avio_wb24

Signed-off-by: Martin Storsjö <martin@martin.st>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  movenc: Simplify code by using avio_wb24
  bfin: unbreak compilation

Merged-by: Michael Niedermayer <michaelni@gmx.at>
mpegvideo_enc: factor expression out

Fixes "warning: dc[0..5] may be used uninitialized in this function"

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