psu-ng: Handle health rollup based on availability

When a PSU is set to not available, create an association between the
power supply and its chassis as a way to 'roll up' the health status to
that chassis.  It looks like:

    <chassis>/critical
        endpoints: <power supply>
    <power supply>/health_rollup
        endpoints: <chassis>

There is Redfish code that look at the endpoints in that chassis
association object to determine if the chassis health is OK or not.

Note that some systems, such as IBM's, have other code that will fill
in that association when it is called out in an event log, which is why
this code doesn't have to do it for every single fault.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I262dd738ebadb72aa207011941066fc282bfe4df
diff --git a/phosphor-power-supply/test/mock.hpp b/phosphor-power-supply/test/mock.hpp
index 706aea4..edfe7a8 100644
--- a/phosphor-power-supply/test/mock.hpp
+++ b/phosphor-power-supply/test/mock.hpp
@@ -55,6 +55,10 @@
                 (sdbusplus::bus::bus & bus, const std::string& invpath,
                  bool available),
                 (const, override));
+    MOCK_METHOD(void, handleChassisHealthRollup,
+                (sdbusplus::bus::bus & bus, const std::string& invpath,
+                 bool addRollup),
+                (const, override));
 };
 
 class MockedGPIOInterface : public GPIOInterfaceBase