cfg80211: Call reg_notifier for self managed hints conditionally

Currently the regulatory core does not call the regulatory callback
reg_notifier for self managed wiphys, but regulatory_hint_user() call is
independent of wiphy and is meant for all wiphys in the system. Even a
self managed wiphy may be interested in regulatory_hint_user() to know
the country code from a trusted regulatory domain change like a cellular
base station. Therefore, for the regulatory source
NL80211_REGDOM_SET_BY_USER and the user hint type
NL80211_USER_REG_HINT_CELL_BASE, call the regulatory notifier.

No current wlan driver uses the REGULATORY_WIPHY_SELF_MANAGED flag while
also registering the reg_notifier regulatory callback, therefore there
will be no impact on existing drivers without them being explicitly
modified to take advantage of this new possibility.

Signed-off-by: Amar Singhal <asinghal@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>