swscale: fix another yuv range conversion overflow in 16bit scaling.

(cherry picked from commit 81cc7d0bd1)

libswscale/swscale.c

@@ -2001,7 +2001,7 @@ static void lumRangeToJpeg16_c(int16_t *_dst, int width)
     int i;
     int32_t *dst = (int32_t *) _dst;
     for (i = 0; i < width; i++)
-        dst[i] = (FFMIN(dst[i],30189<<4)*19077 - (39057361<<4))>>14;
+        dst[i] = (FFMIN(dst[i],30189<<4)*4769 - (39057361<<2))>>12;
 }
 static void lumRangeFromJpeg16_c(int16_t *_dst, int width)
 {