rtw88: power on again if it was already on

We could fail to power on because it was already on. If the return
value is -EALREADY, power off and then power on again to turn on the
hardware as expected.

Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>