pinctrl: sh-pfc: r8a7795: Add SCIF support

Add pins, groups, and functions for all SCIF serial ports on R-Car H3
ES2.0.

Extracted from a big patch in the BSP by Takeshi Kihara.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Takeshi Kihara <takeshi.kihara.df@renesas.com>