ath6kl: Wait for host sleep mode cmd processed event during WOW suspend

ath6kl: Wait for host sleep mode cmd processed event during WOW suspend

For every WMI_SET_HOST_SLEEP_MODE_CMDID command (send from the host),
the firmware sends WMI_SET_HOST_SLEEP_MODE_CMD_PROCESSED_EVENTID as
an acknowledgement to the host.

In order to being sync with the firmware, the host has to wait for
WMI_SET_HOST_SLEEP_MODE_CMD_PROCESSED_EVENT event before going to
the suspend state. This patch ensures ath6kl_wow_suspend() waits
until it gets this event after sending set host sleep mode command.

This patch adds,
 * New command WMI_SET_HOST_SLEEP_MODE_CMD_PROCESSED_EVENTID in
   WMI event table.
 * New WMI function ath6kl_wmi_host_sleep_mode_cmd_prcd_evt_rx()
   to process the event.
 * New flag HOST_SLEEP_MODE_CMD_PROCESSED in VIF flags to record
   the arrival of the event.

Signed-off-by: Raja Mani <rmani@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>