Merge branch 'fix-lockdep-warning-for-htab-of-map'

Hou Tao says:

====================
The patch set fixes a lockdep warning for htab of map. The
warning is found when running test_maps. The warning occurs when
htab_put_fd_value() attempts to acquire map_idr_lock to free the map id
of the inner map while already holding the bucket lock (raw_spinlock_t).

The fix moves the invocation of free_htab_elem() after
htab_unlock_bucket() and adds a test case to verify the solution.
====================

Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>