soc: renesas: Use menu for Renesas SoC

Renesas related SoC settings are located on TOP level menu,
thus it is very verbose.
This patch groups Renesas related settings into
"Renesas SoC driver support" menu.

And it aligns config menu names.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87k0xxho7t.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>