fjes: Do not load fjes driver if system does not have extended socket device.

The fjes driver is used only by FUJITSU servers and almost of all
servers in the world never use it. But currently if ACPI PNP0C02
is defined in the ACPI table, the following message is always shown:

 "FUJITSU Extended Socket Network Device Driver - version 1.2
  - Copyright (c) 2015 FUJITSU LIMITED"

The message makes users confused because there is no reason that
the message is shown in other vendor servers.

To avoid the confusion, the patch adds a check that the server
has a extended socket device or not.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
CC: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>