The regulator will be enabled when initializing the PCIe host and
disabled either as part of the init process or when shutting down the
host.
+- vph-supply: Should specify the regulator in charge of VPH one of the three
+ PCIe PHY powers. This regulator can be supplied by both 1.8v and 3.3v voltage
+ supplies.
Additional required properties for imx6sx-pcie:
- clock names: Must include the following additional entries: