pixblockdsp: Have function pointer prototype match implementation

libavcodec/pixblockdsp.c(58) : warning C4028: formal parameter 1 different from declaration
libavcodec/pixblockdsp.c(63) : warning C4028: formal parameter 1 different from declaration
libavcodec/pixblockdsp.c(66) : warning C4028: formal parameter 1 different from declaration

libavcodec/pixblockdsp.h

@@ -21,13 +21,15 @@
 
 #include <stdint.h>
 
+#include "config.h"
+
 #include "avcodec.h"
 
 typedef struct PixblockDSPContext {
-    void (*get_pixels)(int16_t *block /* align 16 */,
+    void (*get_pixels)(int16_t *restrict block /* align 16 */,
                        const uint8_t *pixels /* align 8 */,
                        ptrdiff_t stride);
-    void (*diff_pixels)(int16_t *block /* align 16 */,
+    void (*diff_pixels)(int16_t *restrict block /* align 16 */,
                         const uint8_t *s1 /* align 8 */,
                         const uint8_t *s2 /* align 8 */,
                         ptrdiff_t stride);