locking/lockdep: Rework lockdep_lock

commit 248efb21 upstream.

A few sites want to assert we own the graph_lock/lockdep_lock, provide
a more conventional lock interface for it with a number of trivial
debug checks.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200313102107.GX12561@hirez.programming.kicks-ass.net


Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>