pinctrl: renesas: r8a7779: Add bias pinconf support

Implement support for pull-up handling for the R-Car H1 SoC, using the
common R-Car bias handling.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/dd966cfc916ef881051ec53bc3393dce7eea8e03.1679328215.git.geert+renesas@glider.be