DACK is done right after the hardware has been turned on, which
means it will be done every time we leave the IDLE state.
But it takes ~2 seconds to finish DACK.

We can back up the results and restore them. And it only takes a few
milliseconds to restore the results to the hardware, saving a lot of
time.
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>