Unify the check on decoder refresh_frame_flag

For both KEY_FRAME and non-KEY_FRAME types, pbi->refresh_frame_flag has
been set up accordingly. There is no need to further check on the frame
type before using this flag.

Change-Id: I909d367e2eb01b1b7f9c52f5c9cde5e6750d0de4

av1/decoder/decodeframe.c

diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 436506a..ca70f37 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -2843,8 +2843,7 @@
   if (cm->seq_params.frame_id_numbers_present_flag) {
     /* If bitmask is set, update reference frame id values and
        mark frames as valid for reference */
-    int refresh_frame_flags =
-        cm->frame_type == KEY_FRAME ? 0xFF : pbi->refresh_frame_flags;
+    int refresh_frame_flags = pbi->refresh_frame_flags;
     for (int i = 0; i < REF_FRAMES; i++) {
       if ((refresh_frame_flags >> i) & 1) {
         cm->ref_frame_id[i] = cm->current_frame_id;