net: phy: broadcom: add support for BCM89610 PHY

It adds support for BCM89610 (Single-Port 10/100/1000BASE-T)
transceiver which is used in P3310 Tegra186 platform.

Signed-off-by: Bhadram Varka <vbhadram@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>