arm64: dts: renesas: ulcb-kf: add dr_mode property for USB2.0 channel 0

ULCB-KF has a USB2.0 dual-role channel (CN13).
This adds dr_mode property for USB2.0 channel 0 (EHCI/OHCI and HS-USB)
as "otg".

Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>