Adding in support for regulators here creates several headaches.
 - Boards that declare their own regulator cannot use this function.
 - Multiple calls to this function require special handling.
 - Boards that declare id's other than '0' need special handling.

Now that there is a simple regulator_register_fixed, we can push
this registration back into the board files.
Signed-off-by: Russ Dill <russ.dill@ti.com>
Tested-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>