pinctrl: renesas: r8a779f0: Add Ethernet pins, groups, and functions

Add pins, groups, and functions for the Ethernet Time-Sensitive
Networking (TSN) interfaces on the Renesas R-Car S4-8 (R8A779F0) SoC.

Based on a larger patch in the BSP by LUU HOAI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/e0a1dc7d2435d28811e3acb361dae050eb3aabc9.1645457792.git.geert+renesas@glider.be