Fix 404 on Hypervisor Reset

/redfish/v1/Systems/hypervisor/Actions/ComputerSystem.Reset was
returning a 404. On closer inspection, it was due to hitting the System
.Reset Action and not making it to the Hypervisor specific action. [1].

Remove the Hypervisor specific action and call the method from the
System .Reset Action. This is how we do the handleHypervisorSystemGet
already.

Believe this was broke by 7f3e84a151. [2] It is only now being
discovered due to a recent rebase with upstream.

Follow the commit before and put this behind the new Hypervisor Computer
System Option.

[1]: https://github.com/openbmc/bmcweb/blob/cd504a94c827fbc98908b2a712f49ea0adf7aab8/redfish-core/lib/systems.hpp#L3493
[2]: https://github.com/openbmc/bmcweb/commit/7f3e84a151e106d9227d08358e9ee3fd225b34c4

Tested: On Patchset 2,
/redfish/v1/Systems/hypervisor/Actions/ComputerSystem.Reset returns a
204.

Change-Id: I3599bb8419604d71684ce61ca992f4b87c1d3fa5
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/redfish-core/lib/systems.hpp b/redfish-core/lib/systems.hpp
index f90bb83..4ad92dd 100644
--- a/redfish-core/lib/systems.hpp
+++ b/redfish-core/lib/systems.hpp
@@ -2872,6 +2872,16 @@
     {
         return;
     }
+
+    if constexpr (BMCWEB_HYPERVISOR_COMPUTER_SYSTEM)
+    {
+        if (systemName == "hypervisor")
+        {
+            handleHypervisorSystemResetPost(req, asyncResp);
+            return;
+        }
+    }
+
     if (systemName != BMCWEB_REDFISH_SYSTEM_URI_NAME)
     {
         messages::resourceNotFound(asyncResp->res, "ComputerSystem",