Fix LLDP driver manager call drivers routine

If a user configures more than one type of LLDP agent driver, only
the first will get called by the _call_drivers routine.

This would affect calls to update, configure the system name,
or clear agents / neighbours.

Closes-Bug: #1798402
Change-Id: I2439f5d738592a909b1703d18a0550439aa2642f
Signed-off-by: Steven Webster <steven.webster@windriver.com>

sysinv/sysinv/sysinv/sysinv/agent/lldp/manager.py

@@ -100,9 +100,9 @@ class SysinvLldpDriverManager(NamedExtensionManager):
             try:
                 method = getattr(driver.obj, method_name)
                 if attr:
-                    return method(attr)
+                    method(attr)
                 else:
-                    return method()
+                    method()
             except Exception as e:
                 LOG.exception(e)
                 LOG.error(