pinctrl: renesas: r8a7795: Optimize pinctrl image size for R8A774E1

This driver supports both RZ/G2H and R-Car H3 SoCs.
Optimize pinctrl image size for RZ/G2H, when support for R-Car H3
(R8A7795) is not enabled

Based on the similar patch on Linux.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>