phy: socionext: Add UniPhier USB3 PHY driver

phy: socionext: Add UniPhier USB3 PHY driver

Add USB3 PHY driver support to control clocks and resets needed to enable
PHY. The phy_ops->init() and exit() control PHY clocks and resets only,
and clocks and resets for the controller and the parent logic are enabled
in advance.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Marek Vasut <marex@denx.de>