regulator: Factor out common enable code

In preparation of being able to enable/disable GPIO regulators, the
code that will be shared among the two kinds to regulators is factored
out into its own source files.

Signed-off-by: Sven Schwermer <sven@svenschwermer.de>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
5 files changed