drivers/net/ethernet: Add ethernet dir and config option

This is the initial patch to organize the drivers/net directory
structure and networking device driver config options.  This patch
does the following:
  - add drivers/net/ethernet/Kconfig
  - integrate the new files into the existing config
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/Kconfig

@@ -193,6 +193,8 @@ source "drivers/net/phy/Kconfig"
 #	Ethernet
 #
 
+source "drivers/net/ethernet/Kconfig"
+
 menuconfig NET_ETHERNET
 	bool "Ethernet (10 or 100Mbit)"
 	depends on !UML

drivers/net/Makefile

 #
-# Makefile for the Linux network (ethercard) device drivers.
+# Makefile for the Linux network device drivers.
 #
 
 obj-$(CONFIG_MII) += mii.o

drivers/net/ethernet/Kconfig

+#
+# Ethernet LAN device configuration
+#
+
+menuconfig ETHERNET
+	bool "Ethernet driver support"
+	depends on NET
+	default y
+	---help---
+	  This section contains all the Ethernet device drivers.
+
+if ETHERNET
+
+endif # ETHERNET

drivers/net/ethernet/Makefile

+#
+# Makefile for the Linux network Ethernet device drivers.
+#