pinctrl: renesas: r8a7790: Optimize pinctrl image size for R8A7742

This driver supports both RZ/G1H and R-Car H2 SoCs.
Optimize pinctrl image size for RZ/G1H, when support for R-Car H2
(R8A7790) is not enabled.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20201019124258.4574-6-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>