Reimplement the hw-lock module to use the new mutex API.  This slightly
changes the semantics of locking a hw-lock as the new mutex API does not
allow timeouts.  When a hwlock_acquire() with a (non-infinite) timeout
is attempted, a warning is printed to the serial console.

Additionally, instead of returning -EINVAL on use of a non-existent
hardware lock, the new implementation triggers a firmware panic.

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