rsi: Set wowlan flag while writing wowlan config parameters

As wowlan enable flag did not set, while writing wowlan parameters to
card using rsi_send_vap_dynamic_update, which results firmware is unable to
set wowlan configurations. Hence, setting wowlan flag before sending
parameters.

Signed-off-by: Siva Rebbagondla <siva.rebbagondla@redpinesignals.com>
Signed-off-by: Sushant Kumar Mishra <sushant.mishra@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>