ff_dot_product(): change return value to int64_t

Idea-by: Vitor
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/celp_math.c

@@ -197,7 +197,7 @@ int ff_log2(uint32_t value)
     return (power_int << 15) + value;
 }
 
-int ff_dot_product(const int16_t *a, const int16_t *b, int length)
+int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length)
 {
     int i;
     int64_t sum = 0;

libavcodec/celp_math.h

@@ -71,7 +71,7 @@ static inline int bidir_sal(int value, int offset)
  *
  * @return dot product = sum of elementwise products
  */
-int ff_dot_product(const int16_t *a, const int16_t *b, int length);
+int64_t ff_dot_product(const int16_t *a, const int16_t *b, int length);
 
 /**
  * returns the dot product.