pinctrl: renesas: r8a779g0: Add INTC-EX pins, groups, and function

Add pins, groups, and function for the Interrupt Controller for External
Devices (INTC-EX) on the Renesas R-Car V4H (R8A779G0) SoC.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/9c33c36d13a5e38d79fa53085339b14631888b50.1718378943.git.geert+renesas@glider.be