pseq: Create UCD90xDevice class

Create the UCD90xDevice class in the phosphor-power-sequencer
application.

This is a base class for the UCD90x family of power sequencer devices.

Tested:
* Performed the following tests on Rainier and Everest systems
  * MFR_STATUS value obtained successfully
  * Verified error paths and exceptions thrown

Change-Id: I430ffb95d96e228ce0245ae1c9cb63db72d590c5
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/test/meson.build b/phosphor-power-sequencer/test/meson.build
index 2a15f0a..b915859 100644
--- a/phosphor-power-sequencer/test/meson.build
+++ b/phosphor-power-sequencer/test/meson.build
@@ -6,6 +6,7 @@
                 'pmbus_driver_device_tests.cpp',
                 'rail_tests.cpp',
                 'standard_device_tests.cpp',
+                'ucd90x_device_tests.cpp',
                 dependencies: [
                     gmock,
                     gtest,