cfg80211: Add backport flag for user cellular base hint

Upstream commit aced43ce ("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>