We can simply pass the regulator name via of_get_property() instead of making
a copy via kstrdup().

This leads to some code simplification.
Suggested-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NMark Brown <broonie@linaro.org>