jpeg2000dec: merge struct field types from j2k

Fixes AVOption type mismatch
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/jpeg2000dec.c

@@ -80,12 +80,13 @@ typedef struct Jpeg2000DecoderContext {
 
     int             bit_index;
 
-    int16_t         curtileno;
+    int             curtileno;
+
     Jpeg2000Tile    *tile;
 
     /*options parameters*/
-    int16_t         lowres;
-    int16_t         reduction_factor;
+    int             lowres;
+    int             reduction_factor;
 } Jpeg2000DecoderContext;
 
 /* get_bits functions for JPEG2000 packet bitstream