pinctrl: sh-pfc: r8a7795: Add MSIOF pins, groups, and functions

Extracted from a big patch by Takeshi Kihara.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[geert: Correct MSIOF3 TXD_A/RXD_A pins]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>