Add SMPTE240M transfer characteristics flag.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavcodec/avcodec.h

@@ -489,6 +489,7 @@ enum AVColorTransferCharacteristic{
     AVCOL_TRC_UNSPECIFIED = 2,
     AVCOL_TRC_GAMMA22     = 4, ///< also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM
     AVCOL_TRC_GAMMA28     = 5, ///< also ITU-R BT470BG
+    AVCOL_TRC_SMPTE240M   = 7,
     AVCOL_TRC_NB             , ///< Not part of ABI
 };