pseq: Add base and UCD90320 device monitor classes

Add a power sequencer device monitoring base class and a UCD90320
subclass. Update power controller class to construct and pass device
information to device class.  Update build file to support.

Signed-off-by: Jim Wright <jlwright@us.ibm.com>
Change-Id: Idf3ef53011b23f15841d93795f9f0995892b10b9
diff --git a/phosphor-power-sequencer/src/power_sequencer_monitor.hpp b/phosphor-power-sequencer/src/power_sequencer_monitor.hpp
new file mode 100644
index 0000000..e714d08
--- /dev/null
+++ b/phosphor-power-sequencer/src/power_sequencer_monitor.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+namespace phosphor::power::sequencer
+{
+
+/**
+ * @class PowerSequencerMonitor
+ * Define a base class for monitoring a power sequencer device.
+ */
+class PowerSequencerMonitor
+{
+  public:
+    PowerSequencerMonitor() = default;
+    PowerSequencerMonitor(const PowerSequencerMonitor&) = delete;
+    PowerSequencerMonitor& operator=(const PowerSequencerMonitor&) = delete;
+    PowerSequencerMonitor(PowerSequencerMonitor&&) = delete;
+    PowerSequencerMonitor& operator=(PowerSequencerMonitor&&) = delete;
+    virtual ~PowerSequencerMonitor() = default;
+};
+
+} // namespace phosphor::power::sequencer