Implementing basic LLDP server, should send port_id message

to each port once every 30 seconds.
* Additionally fixes the on-ward passing of LLDP frames through
the switch

The ports on the case are marked 1-8 so this should reflect that
rather than being 0-based

We can send the hostname as well, this can be dynamically allocated

Let's send the model as the system description as well

cmd_parser.h

@@ -20,6 +20,7 @@ extern __xdata uint8_t err_status;
 #define HEALTH_PH_STP	4
 #define HEALTH_PH_CMD	5
 #define HEALTH_PHASES	6
+#define HEALTH_LLDP     7
 
 extern __xdata uint16_t health_rx_frames;
 #define health_rx_frame()	health_rx_frames++