psu-ng: Updates to get VPD data to inventory

Add in code to retrieve the VPD data and populate that data to the D-Bus
inventory properties.

Use the PMBus utilities to retrieve the model (CCIN for IBM power
supplies), part number, serial number, and firmware version information
from the sysfs "files" provided via the device driver.

Only build in IBM VPD data collection and reporting if meson ran with
-Dibm-vpd=true.

Tested:
    Copied SDK build of phospor-psu-monitor with -Dibm-vpd=true to
    Rainier hardware system, verified inventory properties updated/added.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Change-Id: I61688b154ead570e9d9390342596bf7d840f4dce
diff --git a/types.hpp b/types.hpp
index e7287d4..df67013 100644
--- a/types.hpp
+++ b/types.hpp
@@ -10,6 +10,11 @@
 constexpr auto ASSET_IFACE = "xyz.openbmc_project.Inventory.Decorator.Asset";
 constexpr auto PSU_INVENTORY_IFACE =
     "xyz.openbmc_project.Inventory.Item.PowerSupply";
+constexpr auto VERSION_IFACE = "xyz.openbmc_project.Software.Version";
+#ifdef IBM_VPD
+constexpr auto DINF_IFACE = "com.ibm.ipzvpd.DINF";
+constexpr auto VINI_IFACE = "com.ibm.ipzvpd.VINI";
+#endif
 
 constexpr auto ENDPOINTS_PROP = "endpoints";
 constexpr auto MESSAGE_PROP = "Message";