pinctrl: renesas: r8a77990: Optimize pinctrl image size for R8A774C0

This driver supports both RZ/G2E and R-Car E3 SoCs.
Optimize pinctrl image size for RZ/G2E, when support for R-Car E3
(R8A77990) is not enabled.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20201019124258.4574-5-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>