clk: uniphier: Add missing USB SS-PHY clocks

clk: uniphier: Add missing USB SS-PHY clocks

The USB SS-PHY needs its own clock, however, some clocks don't have
clock gates. Define missing clock entries for the PHY as reference
clock.

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