OMAP2+: voltage: reorganize, split code from data

OMAP2+: voltage: reorganize, split code from data

This is a first pass at reorganizing mach-omap2/voltage.c:

- Separate almost all of the data from the code of mach-omap2/voltage.c.
  The code remains in mach-omap2/voltage.c.  The data goes into one
  of several places, depending on what type of data it is:

  - Silicon process/validation data: mach-omap2/opp*_data.c
  - VC (Voltage Controller) data: mach-omap2/vc*_data.c
  - VP (Voltage Processor) data: mach-omap2/vp*_data.c
  - Voltage domain data: mach-omap2/voltagedomains*_data.c

  The ultimate goal is for all this data to be autogenerated, the same
  way we autogenerate the rest of our data.

- Separate VC and VP common data from VDD-specific VC and VP data.

- Separate common voltage.c code from SoC-specific code; reuse common code.

- Reorganize structures to avoid unnecessary memory loss due to unpacked
  fields.

There is much left to be done.  VC code and VP code should be separated out
into vc*.c and vp*.c files.  Many fields in the existing structures are
superfluous, and should be removed.  Some code in voltage.c seems to be
duplicated; that code should be moved into functions of its own.  Proper
voltage domain code should be created, as was done with the powerdomain
and clockdomains, and powerdomains should reference voltagedomains.

Thanks to Shweta Gulati <shweta.gulati@ti.com> for comments.  Thanks
to Rajendra Nayak <rnayak@ti.com> for finding and fixing some bugs
that prevented OMAP4 from booting:

   https://patchwork.kernel.org/patch/587311/

His patch has been folded into this one to avoid breaking OMAP4
between patches.  Thanks also to Kevin Hilman <khilman@ti.com> for
finding and fixing a compile problem when !CONFIG_PM:

   http://www.spinics.net/lists/arm-kernel/msg118067.html

His patch has also been folded into this one to avoid breaking
!CONFIG_PM builds.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Shweta Gulati <shweta.gulati@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Kevin Hilman <khilman@ti.com>