ice: Fix a memory leak in an error handling path in 'ice_pf_dcb_cfg()'

If this 'kzalloc()' fails we must free some resources as in all the other
error handling paths of this function.

Fixes: 348048e ("ice: Implement iidc operations")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_dcb_lib.c

@@ -316,8 +316,10 @@ int ice_pf_dcb_cfg(struct ice_pf *pf, struct ice_dcbx_cfg *new_cfg, bool locked)
 
 	/* Notify AUX drivers about impending change to TCs */
 	event = kzalloc(sizeof(*event), GFP_KERNEL);
-	if (!event)
-		return -ENOMEM;
+	if (!event) {
+		ret = -ENOMEM;
+		goto free_cfg;
+	}
 
 	set_bit(IIDC_EVENT_BEFORE_TC_CHANGE, event->type);
 	ice_send_event_to_aux(pf, event);