rtw88: configure firmware after HCI started

rtw88: configure firmware after HCI started

After firmware has been downloaded, driver should send
some information to it through H2C commands. Those H2C
commands are transmitted through TX path.

But before HCI has been started, the TX path is not
working completely. Such as PCI interfaces, the interrupts
are not enabled, hence TX interrupts will not be issued
after H2C skb has been DMAed to the device. And the H2C
skbs will not be released until the device is powered off.

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