pinctrl: sh-pfc: r8a7796: Add USB2.0 host pins, groups and functions

This patch adds USB{0,1} (USB2.0 host) pins, groups and functions to
R8A7796 SoC.

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>