regulators: Enhance config file parser

Enhance JSON config file parser to convert relative inventory paths to
absolute form.

Tested:
Run local CI with -Dlong-tests=enabled to enable tests for
validate-regulators-config.py.

Signed-off-by: Bob King <Bob_King@wistron.com>
Change-Id: I80237a673f9c5918898db15363847722141388e6
diff --git a/phosphor-regulators/test/test_utils.hpp b/phosphor-regulators/test/test_utils.hpp
index f56dc18..2903d3c 100644
--- a/phosphor-regulators/test/test_utils.hpp
+++ b/phosphor-regulators/test/test_utils.hpp
@@ -67,7 +67,8 @@
 
     // Create Device
     bool isRegulator = true;
-    std::string fru = "/system/chassis/motherboard/reg1";
+    std::string fru =
+        "/xyz/openbmc_project/inventory/system/chassis/motherboard/reg1";
     std::unique_ptr<i2c::I2CInterface> i2cInterface = createI2CInterface();
     std::unique_ptr<PresenceDetection> presenceDetection{};
     std::unique_ptr<Configuration> configuration{};