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/test/mock_device.hpp b/phosphor-power-sequencer/test/mock_device.hpp
index 7edd3ae..3b218cd 100644
--- a/phosphor-power-sequencer/test/mock_device.hpp
+++ b/phosphor-power-sequencer/test/mock_device.hpp
@@ -43,6 +43,10 @@
     MOCK_METHOD(const std::string&, getName, (), (const, override));
     MOCK_METHOD(uint8_t, getBus, (), (const, override));
     MOCK_METHOD(uint16_t, getAddress, (), (const, override));
+    MOCK_METHOD(const std::string&, getPowerControlGPIOName, (),
+                (const, override));
+    MOCK_METHOD(const std::string&, getPowerGoodGPIOName, (),
+                (const, override));
     MOCK_METHOD(const std::vector<std::unique_ptr<Rail>>&, getRails, (),
                 (const, override));
     MOCK_METHOD(std::vector<int>, getGPIOValues, (Services & services),