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

drivers/soc/renesas/Kconfig

 # SPDX-License-Identifier: GPL-2.0
-config SOC_RENESAS
+menuconfig SOC_RENESAS
 	bool "Renesas SoC driver support" if COMPILE_TEST && !ARCH_RENESAS
 	default y if ARCH_RENESAS
 	select SOC_BUS