phy: Add SATA3 PHY support for Broadcom NSP SoC

This patch adds support for Broadcom NSP SATA3 PHY in existing
Broadcom SATA PHY driver.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>