The twl4030 PMIC needs to be configured properly for things like
warm reset and deeper idle states so the PMIC manages the regulators
properly based on the hardware triggers from the SoC. Earlier
we have configured twl4030 using platform data, but we want to
do it for device tree based booting also.

In some cases configuring twl4030 is needed for things to work.
For example, when rebooting an OMAP3530 at 125 MHz, it hangs.
With this patch, TWL4030 will be reset when a warm reset occures,
and OMAP3530 does not hang on reboot.

Let's add device tree support and configure things for warm reset
as the default when compatible = "ti,twl4030-power". More
complicated configurations can be added to the driver based on
other compatible flags.

Note we now also make the pdata const like it should be.
This allows use it for match->data with the device tree
related functions.

Based on earlier patch by Matthias Brugger <matthias.bgg@gmail.com>
and Lesly A M <leslyam@ti.com>.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>