flicvideo: increase error level and fix error message in CHECK_PIXEL_PTR()

Also return AVERROR_INVALIDDATA rather than -1.
Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>

libavcodec/flicvideo.c

@@ -61,9 +61,9 @@
 
 #define CHECK_PIXEL_PTR(n) \
     if (pixel_ptr + n > pixel_limit) { \
-        av_log (s->avctx, AV_LOG_INFO, "Problem: pixel_ptr >= pixel_limit (%d >= %d)\n", \
+        av_log (s->avctx, AV_LOG_ERROR, "Invalid pixel_ptr = %d > pixel_limit = %d\n", \
         pixel_ptr + n, pixel_limit); \
-        return -1; \
+        return AVERROR_INVALIDDATA; \
     } \
 
 typedef struct FlicDecodeContext {