ARM: dts: iwg20d-q7: Enable HS-USB

Enable HS-USB device for the iWave G20D-Q7 carrier board based on
RZ/G1M.
Also disable the host mode support on usb otg port by default to avoid
pin conflicts.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Chris Paterson <chris.paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>