Fix forward keyframes when kf_min_dist = kf_max_dist.

The flag AOM_EFLAG_FORCE_KF is required only for first pass. Hence removed in other cases. This fixes issues in forward key frames when kf_min_dist = kf_max_dist.

Change-Id: I40909bdab30a74315c559bb0058ea23776cde47d
(cherry picked from commit 3bed0b259b57bfc249e48460fa6831348865f1f5)
diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index ebad4c7..88da193 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -2058,12 +2058,14 @@
   }
 
   // Handle fixed keyframe intervals
-  if (ctx->cfg.kf_mode == AOM_KF_AUTO &&
-      ctx->cfg.kf_min_dist == ctx->cfg.kf_max_dist) {
-    if (cpi->common.spatial_layer_id == 0 &&
-        ++ctx->fixed_kf_cntr > ctx->cfg.kf_min_dist) {
-      flags |= AOM_EFLAG_FORCE_KF;
-      ctx->fixed_kf_cntr = 1;
+  if (is_stat_generation_stage(cpi)) {
+    if (ctx->cfg.kf_mode == AOM_KF_AUTO &&
+        ctx->cfg.kf_min_dist == ctx->cfg.kf_max_dist) {
+      if (cpi->common.spatial_layer_id == 0 &&
+          ++ctx->fixed_kf_cntr > ctx->cfg.kf_min_dist) {
+        flags |= AOM_EFLAG_FORCE_KF;
+        ctx->fixed_kf_cntr = 1;
+      }
     }
   }