feat(hw-locks): Introduce new hw-lock API

Re-add a `hwlock_acquire()` method, but this time without a timeout
parameter.  From a functional point of view, this is just a wrapper
around `mutex_lock()`.

Additionally, add `hwlock_acquire_nonblock()` which behaves like
`mutex_trylock()`.

Signed-off-by: Rahix <rahix@rahix.de>