pseq: Create UCD90320Device class

Create the UCD90320Device class in the phosphor-power-sequencer
application.

This class represents the UCD90320 power sequencer device.

Change-Id: I697644d4c52019be045286a5598023602b7fc4d6
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/test/ucd90x_device_tests.cpp b/phosphor-power-sequencer/test/ucd90x_device_tests.cpp
index 2ec8b2e..3ab5369 100644
--- a/phosphor-power-sequencer/test/ucd90x_device_tests.cpp
+++ b/phosphor-power-sequencer/test/ucd90x_device_tests.cpp
@@ -46,7 +46,8 @@
  * @param gpio GPIO line to read to determine the pgood status of the rail
  * @return Rail object
  */
-std::unique_ptr<Rail> createRail(const std::string& name, unsigned int gpioLine)
+static std::unique_ptr<Rail> createRail(const std::string& name,
+                                        unsigned int gpioLine)
 {
     std::optional<std::string> presence{};
     std::optional<uint8_t> page{};