regulator: Set MODULE_ALIAS for regulator drivers

Several of the regulator drivers didn't have MODULE_ALIAS so couldn't be
auto loaded. Add the MODULE_ALIAS in case they do get built as modules.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>