Add placeholder method peth_port_power() to PowerEthernet class; overrides

to actually return data in Cisco, Extreme and HP classes.

Info/PowerEthernet.pm

@@ -89,6 +89,10 @@ sub peth_port_ifindex {
     return $peth_port_ifindex;
 }
 
+sub peth_port_power {
+    return {};
+}
+
 1;
 
 __END__
@@ -174,6 +178,16 @@ class of the device being powered.
 
 C<pethPsePortPowerClassifications>
 
+=item $poe->peth_port_power()
+
+Power sourced: if status is delivering power, this represents the actual
+power output to the device being powered. This is not included in the MIB,
+but we include a placeholder for the function so it can be included in 
+device classes in a uniform manner. 
+
+Currently the Cisco, Extreme and HP classes override this method to return 
+actual values. 
+
 =item $poe->peth_port_ifindex()
 
 A mapping function from the C<pethPsePortTable> INDEX of