avcodec/utils: add GBRP16 to avcodec_align_dimensions2()

Fixes Ticket3869
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 3fe9e7be)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/utils.c

@@ -374,6 +374,8 @@ void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
     case AV_PIX_FMT_GBRP12BE:
     case AV_PIX_FMT_GBRP14LE:
     case AV_PIX_FMT_GBRP14BE:
+    case AV_PIX_FMT_GBRP16LE:
+    case AV_PIX_FMT_GBRP16BE:
         w_align = 16; //FIXME assume 16 pixel per macroblock
         h_align = 16 * 2; // interlaced needs 2 macroblocks height
         break;