avcodec/dpx: fix off by 1 in bits_per_color check

Fixes: CID1476303 Bad bit shift operation
Fixes: 34871/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DPX_fuzzer-6331163028357120
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/dpx.c

@@ -242,7 +242,7 @@ static int decode_frame(AVCodecContext *avctx,
         return AVERROR_PATCHWELCOME;
     }
 
-    if (bits_per_color > 32)
+    if (bits_per_color > 31)
         return AVERROR_INVALIDDATA;
 
     buf += 820;
@@ -319,7 +319,7 @@ static int decode_frame(AVCodecContext *avctx,
             minCV = av_int2float(i);
             maxCV = av_int2float(j);
             if (bits_per_color >= 1 &&
-                minCV == 0.0f && maxCV == ((1<<bits_per_color) - 1)) {
+                minCV == 0.0f && maxCV == ((1U<<bits_per_color) - 1)) {
                 avctx->color_range = AVCOL_RANGE_JPEG;
             } else if (bits_per_color >= 8 &&
                        minCV == (1  <<(bits_per_color - 4)) &&