whispser : reset the "batched" timings (#1721)

whisper.cpp

@@ -3821,6 +3821,7 @@ void whisper_reset_timings(struct whisper_context * ctx) {
         ctx->state->t_sample_us = 0;
         ctx->state->t_encode_us = 0;
         ctx->state->t_decode_us = 0;
+        ctx->state->t_batchd_us = 0;
         ctx->state->t_prompt_us = 0;
         ctx->state->n_sample = 0;
         ctx->state->n_encode = 0;