rsi: immediate wakeup bit and priority for TX command packets

For all TX command packets immediate wakeup bit needs to be
set in descriptor. This will make sure device will wakeup if it
is in any sleep state. Priority of the packet is also set.

Signed-off-by: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Signed-off-by: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>