phy: qcom: Add driver for QCOM IPQ806x SATA PHY

Add a PHY driver for uses with AHCI based SATA controller driver on the
IPQ806x family of SoCs.

Signed-off-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>