riscv: defconfig: Enable the Allwinner D1 platform and drivers

riscv: defconfig: Enable the Allwinner D1 platform and drivers

Now that several D1-based boards are supported, enable the platform in
our defconfig. Build in the drivers which are necessary to boot, such as
the pinctrl, MMC, RTC (which provides critical clocks), SPI (for flash),
and watchdog (which may be left enabled by the bootloader). Other common
onboard peripherals are enabled as modules.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20230126045738.47903-12-samuel@sholland.org
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>