phy: rcar-gen2: Add r8a7743/5 support

Add USB PHY support for r8a7743/5 SoC. Renesas RZ/G1[ME] (R8A7743/5)
USB PHY is identical to the R-Car Gen2 family.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>