wcn36xx: only handle packets when ED or DONE bit is set

On RX and TX interrupts, check for the WCN36XX_CH_STAT_INT_ED_MASK or
WCN36XX_CH_STAT_INT_DONE_MASK in the interrupt reason register, and
only handle packets when it is set. This way, reap_tx_dxes() is only
invoked when needed.

This brings the dequeing logic in line with what the prima downstream
driver is doing.

While at it, also log the interrupt reason.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>