pinctrl: renesas: r8a779g0: Add missing FlexRay

This patch adds missing FlexRay pins.
Because Document (Rev.0.51) has 2x FXR_TXENA/B pin with no suffix (_A, _B),
this patch names them as _X.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87pmipsj9a.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>