avcodec/mjpegdec: update cur_scan also for non-LS jpeg

This should make no difference but the variable will be used in a subsequent commit
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mjpegdec.c

@@ -1732,8 +1732,6 @@ int ff_mjpeg_find_marker(MJpegDecodeContext *s,
         int t = 0, b = 0;
         PutBitContext pb;
 
-        s->cur_scan++;
-
         /* find marker */
         while (src + t < buf_end) {
             uint8_t x = src[t++];
@@ -1924,6 +1922,7 @@ eoi_parser:
 
             goto the_end;
         case SOS:
+            s->cur_scan++;
             if ((ret = ff_mjpeg_decode_sos(s, NULL, NULL)) < 0 &&
                 (avctx->err_recognition & AV_EF_EXPLODE))
                 goto fail;