Revert "regmap: maple: Provide lockdep (sub)class for maple tree's internal lock"

This reverts commit 70e2f305 which is
commit 1ed9b927 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I4ccea7a05457a9822718507537c01b63c4af00f5
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>