Add support for the TI DP83848 Ethernet PHY device.

The DP83848 is a highly reliable, feature rich, IEEE 802.3 compliant
single port 10/100 Mb/s Ethernet Physical Layer Transceiver supporting
the MII and RMII interfaces.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>