Web: Handle missing LOS pin

When device has no LOS pin and module has no extended status, the
RX LOS value will not be shown. When both are present, the equality
check is performed. When only one is present, the present value
will be shown.

json from the switch, will still contain the field, but can be
null for when pin is not available.

httpd/page_impl.c

@@ -656,7 +656,11 @@ void send_status(void)
 				for (register uint8_t s = 0; s < 16; s++)
 					outbuf[slen++] = sfp_module_serial[machine.is_sfp[i]-1][s];
 				slen += strtox(outbuf + slen,"\",\"sfp_los\":");
-				bool_to_html(sfp_pins_last & (0x2 << (((machine.is_sfp[i]-1) << 2))));
+				if (machine.sfp_port[machine.is_sfp[i]-1].pin_los == GPIO_NA) {
+					slen += strtox(outbuf + slen,"null");
+				} else {
+					bool_to_html(sfp_pins_last & (0x2 << (((machine.is_sfp[i]-1) << 2))));
+				}
 			} else {
 				bool_to_html(0);
 			}