pinctrl: sh-pfc: r8a7795-es1: Use generic bias register description

Move R-Car H3 ES1.x bias support over to the generic way to describe
bias registers, which will be needed for suspend/resume support.

As the new description is more compact, this decreases kernel size by
ca. 304 bytes.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>