icnss: Avoid sending mode on twice

Do not send mode on request to the firmware, if sent already.
Keep a flag maintianing mode on state, check before sending
mode on request to the firmware and clear the flag once FW ready
is received or mode off is sent to the firmware.

Change-Id: I66ff348b1b25046ee3a40971458475e6b9699c40
Signed-off-by: Anurag Chouhan <achouhan@codeaurora.org>