cfg80211: Add backport flag for user cellular base hint

Upstream commit aced43ce780dc5e683b3de00ce9fb3db7d28e1d3 ("cfg80211: Call
reg_notifier for self managed hints conditionally") adds support
for processing user cell_base hints when wiphy is self managed. Add
backport flag for the same.

Change-Id: I44e083f4346cc95eb2f80eeec7d56f305e7ecce0
CRs-Fixed: 2201959
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>