wifi: rtw89: pci: fix interrupt stuck after leaving low power mode

We turn off interrupt in ISR, and re-enable interrupt in threadfn or
napi_poll according to the mode it stays. If we are turning off interrupt,
rtwpci->running flag is unset and interrupt handler stop processing even
if it was called, so disallow to re-enable interrupt in this situation.
Or, wifi chip doesn't trigger interrupt events anymore because interrupt
status (ISR) isn't clear by interrupt handler anymore.

Fixes: c83dcd05 ("rtw89: pci: add a separate interrupt handler for low power mode")
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220824063312.15784-1-pkshih@realtek.com