pinctrl: renesas: r8a779g0: Add missing SCIF_CLK2 pin group/function

R-Car V4H actually has two SCIF_CLK pins.
The second pin provides the SCIF_CLK signal for HSCIF2 and SCIF4.

Fixes: 050442ae

 ("pinctrl: renesas: r8a779g0: Add pins, groups and functions")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/6352ec9b63fdd38c2c70d8d203e46f21fbfeccdc.1705589612.git.geert+renesas@glider.be