mac80211: set SDATA_STATE_RUNNING for monitor interfaces

During restarrt, mac80211 is supposed to reconfigure the driver.
When there's a monitor interface, the interface is added and the
channel context for it was created, but not assigned to it as it
was not considered running during the restart.

Fix this by setting SDATA_STATE_RUNNING while adding monitor
interfaces.

Signed-off-by: Borwankar, Antara <antara.borwankar@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201129172929.e1df99693a4c.I494579f28018c2d0b9d4083a664cf872c28405ae@changeid


[reword commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>