libvpxenc: Remove duplicate AVOption constants.

Found-by:  j@v2v.cc
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/libvpxenc.c

@@ -574,9 +574,6 @@ static const AVOption options[] = {
 #endif
 {"speed", "", offsetof(VP8Context, cpu_used), AV_OPT_TYPE_INT, {.dbl = 3}, -16, 16, VE},
 {"quality", "", offsetof(VP8Context, deadline), AV_OPT_TYPE_INT, {.dbl = VPX_DL_GOOD_QUALITY}, INT_MIN, INT_MAX, VE, "quality"},
-{"best", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = VPX_DL_BEST_QUALITY}, INT_MIN, INT_MAX, VE, "quality"},
-{"good", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = VPX_DL_GOOD_QUALITY}, INT_MIN, INT_MAX, VE, "quality"},
-{"realtime", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = VPX_DL_REALTIME}, INT_MIN, INT_MAX, VE, "quality"},
 {"arnr_max_frames", "altref noise reduction max frame count", offsetof(VP8Context, arnr_max_frames), AV_OPT_TYPE_INT, {.dbl = 0}, 0, 15, VE},
 {"arnr_strength", "altref noise reduction filter strength", offsetof(VP8Context, arnr_strength), AV_OPT_TYPE_INT, {.dbl = 3}, 0, 6, VE},
 {"arnr_type", "altref noise reduction filter type", offsetof(VP8Context, arnr_type), AV_OPT_TYPE_INT, {.dbl = 3}, 1, 3, VE},