lavc/avcodec.h: fix prolems -> problems typo

libavcodec/avcodec.h

@@ -1253,7 +1253,7 @@ typedef struct AVCodecContext {
      * rv10: additional flags
      * mpeg4: global headers (they can be in the bitstream or here)
      * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
-     * than extradata_size to avoid prolems if it is read with the bitstream reader.
+     * than extradata_size to avoid problems if it is read with the bitstream reader.
      * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
      * - encoding: Set/allocated/freed by libavcodec.
      * - decoding: Set/allocated/freed by user.