rtc: Fix to get_ref_frame_flags for non-rd mode

For fast_nonrd pickmode (real-time speed 8) GOLDEN
is second priority reference and so it should only
be disabled if it's the same as LAST.

This make RTC speed 8 bitexact for the change in 56f4ad4.

Change-Id: I5c4e827ba8d6ecc3b96d969cffb469d68f80611b

av1/encoder/encode_strategy.c

diff --git a/av1/encoder/encode_strategy.c b/av1/encoder/encode_strategy.c
index 39bf26b..27ce6c4 100644
--- a/av1/encoder/encode_strategy.c
+++ b/av1/encoder/encode_strategy.c
@@ -231,22 +231,19 @@
   for (int i = 1; i < INTER_REFS_PER_FRAME; ++i) {
     const RefCntBuffer *const this_ref = ref_frames[i];
     // If this_ref has appeared before, mark the corresponding ref frame as
-    // invalid.
-    for (int j = 0; j < i; ++j) {
+    // invalid. For fast_nonrd mode, only disable GOLDEN_FRAME if it's the same
+    // as LAST_FRAME.
+    int index = (cpi->sf.use_fast_nonrd_pick_mode &&
+                 ref_frame_priority_order[i] == GOLDEN_FRAME)
+                    ? 1
+                    : i;
+    for (int j = 0; j < index; ++j) {
       if (this_ref == ref_frames[j]) {
         flags &= ~(1 << (ref_frame_priority_order[i] - 1));
         break;
       }
     }
   }
-
-  // For non-RD mode, only disable GOLDEN_FRAME if it's the same as LAST_FRAME.
-  if (cpi->sf.use_fast_nonrd_pick_mode) {
-    const RefCntBuffer *last_buf = get_ref_frame_buf(cm, LAST_FRAME);
-    const RefCntBuffer *golden_buf = get_ref_frame_buf(cm, GOLDEN_FRAME);
-    if (golden_buf != last_buf) flags |= (1 << GOLDEN_FRAME);
-  }
-
   return flags;
 }