1-wire: in-kernel notification on device events

Before this patch 1-wire subsystem didn't provide access to its
add/remove events to other parts of the kernel. Now it is possible
to register a standard notifier_block observer, which will be informed
of subsequent device insertions and removals.

The framework is copied from USB subsystem.

Signed-off-by: Sergey Yanovich <ynvich@gmail.com>
ARM: set LP-8x4x serial from built-in 1-wire
ARM: enumerate LP-8x4x parallel modules