float_dsp: Include config.h for redefining restrict

This makes sure that the restrict keyword is mapped to whatever
keyword the compiler prefers/supports. This fixes building on MSVC
(and possibly on GCC 2.x as well).
Signed-off-by: Martin Storsjö <martin@martin.st>

libavutil/float_dsp.h

@@ -19,6 +19,8 @@
 #ifndef AVUTIL_FLOAT_DSP_H
 #define AVUTIL_FLOAT_DSP_H
 
+#include "config.h"
+
 typedef struct AVFloatDSPContext {
     /**
      * Calculate the product of two vectors of floats and store the result in