phy: uniphier-pcie: Add legacy SoC support for Pro5

Add legacy SoC support that needs to manage gio clock and reset and to skip
setting unimplemented phy parameters. This supports Pro5.

This specifies only 1 port use because Pro5 doesn't set it in the power-on
sequence.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>