locking/ww_mutex: Fix ww_mutex dummy lockdep map selftest warnings

The below commit introduces a dummy lockdep map, but didn't get
the initialization quite right (it should mimic the initialization
of the real ww_mutex lockdep maps). It also introduced a separate
locking api selftest failure. Fix these.

Closes: https://lore.kernel.org/lkml/Zw19sMtnKdyOVQoh@boqun-archlinux/


Fixes: 823a5662 ("locking/ww_mutex: Adjust to lockdep nest_lock requirements")
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241127085430.3045-1-thomas.hellstrom@linux.intel.com