UPSTREAM: maple_tree: preserve the tree attributes when destroying maple tree

When destroying maple tree, preserve its attributes and then turn it into
an empty tree.  This allows it to be reused without needing to be
reinitialized.

Link: https://lkml.kernel.org/r/20231027033845.90608-10-zhangpeng.00@bytedance.com


Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

(cherry picked from commit 8e50d32c)

Bug: 308042511
Change-Id: If1725d5a37dcd26bec23e6bffe95d877903dfab1
Signed-off-by: Fangzheng Zhang <fangzheng.zhang@unisoc.com>