ARM: mvebu: fix description of pwr-sata0 regulator on Armada 388 GP

This regulator was lacking the reference to the GPIO that controls it,
and the regulator-min-microvolt and regulator-max-microvolt
properties. Thanks to this commit, the pwr-sata0 regulator now looks
more like the other pwr-sata{1,2,3} regulators in the same Device
Tree, with of course the exception of a different GPIO reference.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>