lavu/fixed_dsp: add missing av_restrict qualifiers

The butterflies_fixed function pointer declaration specifies av_restrict
for the first two pointer arguments. So the corresponding function
definitions should honor this declaration.

MSVC emits warning C4113 for this.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavutil/fixed_dsp.c

@@ -135,7 +135,7 @@ static int scalarproduct_fixed_c(const int *v1, const int *v2, int len)
     return (int)(p >> 31);
 }
 
-static void butterflies_fixed_c(int *v1s, int *v2, int len)
+static void butterflies_fixed_c(int *av_restrict v1s, int *av_restrict v2, int len)
 {
     int i;
     unsigned int *v1 = v1s;

libavutil/x86/fixed_dsp_init.c

@@ -23,7 +23,7 @@
 #include "libavutil/fixed_dsp.h"
 #include "cpu.h"
 
-void ff_butterflies_fixed_sse2(int *src0, int *src1, int len);
+void ff_butterflies_fixed_sse2(int *av_restrict src0, int *av_restrict src1, int len);
 
 av_cold void ff_fixed_dsp_init_x86(AVFixedDSPContext *fdsp)
 {