regulator: lm363x: Add support for LM36274

Adding regulator support for the LM36274 backlight driver.
This device can leverage this existing code as the functionality
and registers are common enough between the LM36274 and the LM363x
series of devices.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>