qlge: Fix build error without CONFIG_ETHERNET

Now if CONFIG_ETHERNET is not set, QLGE driver
building fails:

drivers/staging/qlge/qlge_main.o: In function `qlge_remove':
drivers/staging/qlge/qlge_main.c:4831: undefined reference to `unregister_netdev'
Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 955315b0 ("qlge: Move drivers/net/ethernet/qlogic/qlge/ to drivers/staging/qlge/")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/staging/qlge/Kconfig

@@ -2,7 +2,7 @@
 
 config QLGE
 	tristate "QLogic QLGE 10Gb Ethernet Driver Support"
-	depends on PCI
+	depends on ETHERNET && PCI
 	help
 	This driver supports QLogic ISP8XXX 10Gb Ethernet cards.