gpio: rcar: Remove obsolete platform data support

Since commit 4baadb9e

 ("ARM: shmobile: r8a7778: remove obsolete
setup code"), Renesas R-Car SoCs are only supported in generic DT-only
ARM multi-platform builds.  The driver doesn't need to use platform data
anymore, hence remove platform data configuration.

Make gpio_rcar_priv.has_both_edge_trigger a boolean for consistency with
gpio_rcar_info.has_both_edge_trigger.
Move gpio_rcar_priv.irq_parent down while we're at it, to prevent gaps
on 64-bit.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>