Decoder: Ignore dangling fields during flush

If decoder has decoded one field and is waiting for next field,
and flush is called, then ignore the current decoded field.

This is needed to ensure seek works in case of flush between field
decode calls

Bug: 32391809
Test: Tested manually by decoding clip in the above bug in Photos app

Change-Id: I72bb0385c216ebe262b346a56d3bc8fb97f90a7b

decoder/ih264d_api.c

@@ -2604,6 +2604,9 @@ WORD32 ih264d_set_flush_mode(iv_obj_t *dec_hdl, void *pv_api_ip, void *pv_api_op
 
     ps_ctl_op->u4_error_code = 0;
 
+    /* Ignore dangling fields during flush */
+    ps_dec->u1_top_bottom_decoded = 0;
+
     return IV_SUCCESS;
 }