gpio: rcar: Rework hardware features handling

Reuse gpio_rcar_info inside gpio_rcar_priv instead of duplicating the
individual members, so gpio_rcar_parse_dt() can copy them in one go.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>