icnss: Assign priority for icnss modem notifier callback

This change is to ensure that modem notifier callback for
icnss2 driver gets called before it gets called for IPA.
In one scenerio, wlan driver holds rtnl lock before
trying to send WMI message to wlan fw, During same time
watchdog bite happened on modem and IPA received modem
notifier callback. Here IPA is also trying to hold rtnl lock
which is held by wlan driver which never got released as driver
is not aware of watchdog bite on modem. In this case
icnss driver is not getting modem notifier callback.This
change ensures modem notifier gets called for wlan first
and rtnl lock held by wlan driver gets released.

Change-Id: I9effd300f6b22138baec59a03a9c4bceb87a8130
Signed-off-by: Sandeep Singh <sandsing@codeaurora.org>