avcodec/ffv1enc: Fix storing RGB48 without explicitly set level

the bps value is only stored with level >= 1, using rgb48 with level 0 requires the
user app to keep track of the bps by external means, which does not always happen
also we force level >= 1 for other 16bps formats, so this is consistent.
Found-by: Jerome Martinez <jerome@mediaarea.net>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/ffv1enc.c

@@ -629,6 +629,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
         s->chroma_planes = 1;
         s->bits_per_raw_sample = 16;
         s->use32bit = 1;
+        s->version = FFMAX(s->version, 1);
         if (avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
             av_log(avctx, AV_LOG_ERROR, "16bit RGB is experimental and under development, only use it for experiments\n");
             return AVERROR_INVALIDDATA;