avcodec/exr: Return correct error code on allocation failure

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/exr.c

@@ -2245,7 +2245,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
     // allocate thread data, used for non EXR_RAW compression types
     s->thread_data = av_mallocz_array(avctx->thread_count, sizeof(EXRThreadData));
     if (!s->thread_data)
-        return AVERROR_INVALIDDATA;
+        return AVERROR(ENOMEM);
 
     return 0;
 }