Update power supply inventory path

https://gerrit.openbmc-project.xyz/#/c/8936/ is changing
the power supply inventory path.  See that commit
for the reasoning.

Change-Id: I351bb7300590c2fd260fb6838785e40a729226a0
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/tests/test_inventory.robot b/tests/test_inventory.robot
index e1198c8..38a62ea 100644
--- a/tests/test_inventory.robot
+++ b/tests/test_inventory.robot
@@ -484,8 +484,8 @@
     [Documentation]  Verify minimal power supply inventory.
     [Tags]  Verify_Minimal_Power_Supply_Inventory
     # Example:
-    # "/xyz/openbmc_project/inventory/system/chassis/powersupply0",
-    # "/xyz/openbmc_project/inventory/system/chassis/powersupply1",
+    # "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply0",
+    # "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply1",
 
     # item         minimum_count
     powersupply    1