netdev/fec.c: add phylib supporting to enable carrier detection (v2)

BugLink: http://bugs.launchpad.net/bugs/457878

v2:
 - remove duplicated phy_speed caculation
 - fix the phy_speed caculation according to the DataSheet

v1:
 - removed old MII phy control code
 - add phylib supporting
 - add ethtool interface to make user space NetworkManager works

Tested on Freescale i.MX51 Babbage board.

This patch is based on a patch from Frederic Rodo <fred.rodo@gmail.com>

Cc: Frederic Rodo <fred.rodo@gmail.com>
Signed-off-by: NBryan Wu <bryan.wu@canonical.com>
Acked-by: NAmit Kucheria <amit.kucheria@canonical.com>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -1916,6 +1916,7 @@ config FEC
 	bool "FEC ethernet controller (of ColdFire and some i.MX CPUs)"
 	depends on M523x || M527x || M5272 || M528x || M520x || M532x || \
 		MACH_MX27 || ARCH_MX35 || ARCH_MX25 || ARCH_MX5
+	select PHYLIB
 	help
 	  Say Y here if you want to use the built-in 10/100 Fast ethernet
 	  controller on some Motorola ColdFire and Freescale i.MX processors.