sonic: simplify shift_down()

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

libavcodec/sonic.c

@@ -90,7 +90,7 @@ static inline int shift(int a,int b)
 
 static inline int shift_down(int a,int b)
 {
-    return (a>>b)+((a<0)?1:0);
+    return (a>>b)+(a<0);
 }
 
 #if 1