mac80211: Don't set per-BSS QoS for monitor interfaces

In AP mode, there is no need to notify the driver about QoS
changes for the monitor interface that is created. The warning
in ieee80211_bss_info_change_notify() would be hit otherwise.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>