drivers/net/phy/micrel_phy: Add support for new PHYs

Summary of changes:
.Newly added phys
	-KSZ8081/KSZ8091, which has some phy ids.
	-KSZ8061
	-KSZ9031, which is Gigabit phy.
	-KSZ886X, which has a switch function.
	-KSZ8031, which has a same phy ids with KSZ8021.

Signed-off-by: David J. Choi <david.choi@micrel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>