riscv: configs: defconfig: Enable configs required for RZ/Five SoC

riscv: configs: defconfig: Enable configs required for RZ/Five SoC

Enable the configs required by the below IP blocks which are
present on RZ/Five SoC:
* ADC
* CANFD
* DMAC
* eMMC/SDHI
* OSTM
* RAVB (+ Micrel PHY)
* RIIC
* RSPI
* SSI (Sound+WM8978 codec)
* Thermal
* USB (PHY/RESET/OTG)

Along with the above some core configs are enabled too,
-> CPU frequency scaling as RZ/Five does support this.
-> MTD is enabled as RSPI can be connected to flash chips
-> Enabled I2C chardev so that it enables userspace to read/write
   i2c devices (similar to arm64)
-> Thermal configs as RZ/Five SoC does have thermal unit
-> GPIO regulator as we might have IP blocks for which voltage
   levels are controlled by GPIOs
-> OTG configs as RZ/Five USB can support host/function
-> Gadget configs so that we can test USB function (as done in arm64
   all the gadget configs are enabled)

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230929000704.53217-6-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>