ath6kl: Check wow state before sending control and data pkt

Below two scenarios are taken care in this patch which helped
to fix the firmware crash during wow suspend/resume.

* TX operation (ctrl tx and data tx) has to be controlled based
  on suspend state. i.e, with respect to WOW mode, control packets
  are allowed to send from the host until the suspend state goes
  ATH6KL_STATE_WOW and the data packets are allowed until WOW
  suspend operation starts.

* Similarly, wow resume is NOT allowed if WOW suspend is in progress.

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