aries | p1: mm: remove useless rcu lock-unlock from mapping_tagged()

radix_tree_tagged() is lockless - it reads from a member of the raid-tree
root node.  It does not require any protection.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change-Id: Ia9576b257db346434774b8964f228c16a57c24f9
Merge "aries | p1: mm: remove useless rcu lock-unlock from mapping_tagged()" into android-4.4