Rename getPSUInventoryPath to getPSUInventoryPaths

Rename the utils method/function getPSUInventoryPath() to
getPSUInventoryPaths().  The method/function returns multiple paths in a
vector, so the name should be plural.  This will make the return type
more clear.  Currently the name implies only one path will be returned.

Tested:
* Verified all automated tests build and run successfully
* Verified getPSUInventoryPaths() returns correct data

Change-Id: I7e215c37e3ce1eb27313bc51348c7f7335c8f67a
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/test/mocked_utils.hpp b/test/mocked_utils.hpp
index 873c73b..7c293cf 100644
--- a/test/mocked_utils.hpp
+++ b/test/mocked_utils.hpp
@@ -16,7 +16,7 @@
 
     ~MockedUtils() override = default;
 
-    MOCK_CONST_METHOD1(getPSUInventoryPath,
+    MOCK_CONST_METHOD1(getPSUInventoryPaths,
                        std::vector<std::string>(sdbusplus::bus_t& bus));
 
     MOCK_CONST_METHOD3(getService,