avfilter/vf_convolution: add 16-column operation for filter_column()

Based on patch by Xu Jun <xujunzz@sjtu.edu.cn>

libavfilter/convolution.h

@@ -57,7 +57,7 @@ typedef struct ConvolutionContext {
     void (*filter[4])(uint8_t *dst, int width,
                       float rdiv, float bias, const int *const matrix,
                       const uint8_t *c[], int peak, int radius,
-                      int dstride, int stride);
+                      int dstride, int stride, int size);
 } ConvolutionContext;
 
 void ff_convolution_init_x86(ConvolutionContext *s);

libavfilter/x86/vf_convolution_init.c

@@ -27,7 +27,7 @@
 void ff_filter_3x3_sse4(uint8_t *dst, int width,
                         float rdiv, float bias, const int *const matrix,
                         const uint8_t *c[], int peak, int radius,
-                        int dstride, int stride);
+                        int dstride, int stride, int size);
 
 av_cold void ff_convolution_init_x86(ConvolutionContext *s)
 {