regulator: pass additional of_node to regulator_register()

With device tree support for regulators, its needed that the
regulator_dev->dev device has the right of_node attached.
To be able to do this add an additional parameter to the
regulator_register() api, wherein the dt-adapted driver can
then pass this additional info onto the regulator core.

Change-Id: Idf7c4e532cc06fd00b8182b635d15dcfafb2cef9
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
[mbohan: Update regulator_register for msm regulator drivers]
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>