Turn on two-steps scaling in VP9 encoder dynamic resizing.

First do a 3/4 scaling and then go down to 1/2 when necessary.

Change-Id: I5689c5228ca7e1606baea7f960eb24d0dab04d4d

vp9/encoder/vp9_ratectrl.h

@@ -26,7 +26,7 @@ extern "C" {
 
 #define MIN_GF_INTERVAL     4
 #define MAX_GF_INTERVAL     16
-#define ONEHALFONLY_RESIZE  1
+#define ONEHALFONLY_RESIZE  0
 
 typedef enum {
   INTER_NORMAL = 0,