Add support for the reset controller that's used on the i.MX7D
and i.MX8MQ. This will be needed to be able to assert the PCIe
reset pins. Bindings taken from Linux, driver implementation
mostly taken from Linux and adjusted to U-Boot infrastructure.
Signed-off-by: Patrick Wildt <patrick@blueri.se>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
