Fix function pointer type to match function it is assigned.

libswscale/swscale_template.c

@@ -2406,7 +2406,7 @@ static inline void RENAME(hyscale)(SwsContext *c, uint16_t *dst, long dstWidth,
                                    uint32_t *pal, int isAlpha)
 {
     void (*toYV12)(uint8_t *, const uint8_t *, long, uint32_t *) = isAlpha ? c->alpToYV12 : c->lumToYV12;
-    void (*convertRange)(uint16_t *, int) = isAlpha ? NULL : c->lumConvertRange;
+    void (*convertRange)(int16_t *, int) = isAlpha ? NULL : c->lumConvertRange;
 
     src += isAlpha ? c->alpSrcOffset : c->lumSrcOffset;