MII: fix Kconfig dependencies for MII

MII Kconfig option is apart of the core networking drivers and
by default NET_CORE is enabled so drivers selecting MII will
have MII enabled as well.  It was found using the randconfig
option during testing, MII would be selected but NET_CORE
could be disabled.  This caused a dependency error.

Resolved the dependency by selecting NET_CORE when MII is
selected.

Reported-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index 1f64747..6dff5a0 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -62,6 +62,7 @@
 	tristate "JMicron(R) PCI-Express Gigabit Ethernet support"
 	depends on PCI
 	select CRC32
+	select NET_CORE
 	select MII
 	---help---
 	  This driver supports the PCI-Express gigabit ethernet adapters
@@ -102,6 +103,7 @@
 	tristate "Myson MTD-8xx PCI Ethernet support"
 	depends on PCI
 	select CRC32
+	select NET_CORE
 	select MII
 	---help---
 	  Say Y here to support the Myson MTD-800 family of PCI-based Ethernet
@@ -112,6 +114,7 @@
 
 config NET_NETX
 	tristate "NetX Ethernet support"
+	select NET_CORE
 	select MII
 	depends on ARCH_NETX
 	---help---
@@ -128,6 +131,7 @@
 config ETHOC
 	tristate "OpenCores 10/100 Mbps Ethernet MAC support"
 	depends on HAS_IOMEM && HAS_DMA
+	select NET_CORE
 	select MII
 	select PHYLIB
 	select CRC32