Add a PHY driver for the R-Car Gen3 which allows configuring
USB OTG PHY on Gen3 into host mode and toggles VBUS in case a
dedicated regulator is present.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>