pinctrl: sh-pfc: r8a77990: Add I2C{1,2,4,5,6,7} pins, groups and functions

This patch adds I2C{1,2,4,5,6,7} pins, groups and functions to
the R8A77990 SoC.

NOTE: I2C0 and I2C3 are not pin multiplexed.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>