Add support for PHY interface built into ahci controller implemented
in UniPhier Pro4 SoC.

Pro4 SoC distinguishes it from other SoCs as "legacy" SoC, which has GIO
clock line. And Pro4 AHCI-PHY needs to control additional reset lines
("pm", "tx", and "rx").
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1635503947-18250-9-git-send-email-hayashi.kunihiko@socionext.comSigned-off-by: Vinod Koul <vkoul@kernel.org>