w1: masters: omap_hdq: add support for 1-wire mode

This patches makes following changes to omap_hdq driver
- Enable 1-wire mode.
- Implement w1_triplet callback to facilitate search rom
procedure and auto detection of 1-wire slaves.
- Proper enabling and disabling of interrupt.
- Cleanups (formatting and return value checks).

HDQ mode remains unchanged.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Jonathan Corbet <corbet@lwn.net>
CC: Tony Lindgren <tony@atomide.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

w1: omap-hdq: support device probing with device-tree

This driver has no 'compatible' string and so is not found when
using device-tree.

Add one with value to match
hdqw1w: 1w@480b2000 {
device in omap3.dtsi.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>