pseq: Add named GPIO properties

Add the new named GPIO properties from the JSON config file to the
power sequencer device class hierarchy.

New JSON GPIO properties:
* power_control_gpio_name
* power_good_gpio_name

Power sequencer device class hierarchy:
* PowerSequencerDevice   (power_sequencer_device.*)
  * StandardDevice       (standard_device.*)
    * PMBusDriverDevice  (pmbus_driver_device.*)
      * UCD90xDevice     (ucd90x_device.*)
        * UCD90160Device (ucd90160_device.*)
        * UCD90320Device (ucd90320_device.*)

Tested:
* Ran automated tests. All ran successfully.

Change-Id: Idcccee89eb09cb7d135f45aeb4f6dfe8299adf43
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/power_control.cpp b/phosphor-power-sequencer/src/power_control.cpp
index fbf2d5f..fa43ff9 100644
--- a/phosphor-power-sequencer/src/power_control.cpp
+++ b/phosphor-power-sequencer/src/power_control.cpp
@@ -399,12 +399,14 @@
             {
                 device = std::make_unique<UCD90160Device>(
                     deviceProperties->bus, deviceProperties->address,
+                    "power-chassis-control", "power-chassis-good",
                     std::move(rails), services);
             }
             else if (deviceProperties->type == UCD90320Device::deviceName)
             {
                 device = std::make_unique<UCD90320Device>(
                     deviceProperties->bus, deviceProperties->address,
+                    "power-chassis-control", "power-chassis-good",
                     std::move(rails), services);
             }
             else