Drew found "CONFIG_DMA_GLOBAL_POOL=y causes ADMA buffer alloc to fail"
the log looks like:

    mmc0: Unable to allocate ADMA buffers - falling back to standard DMA

The logic is: generic riscv defconfig selects ARCH_RENESAS then
ARCH_R9A07G043 which selects DMA_GLOBAL_POOL, which assumes all
non-dma-coherent riscv platforms have a dma global pool, this assumption
seems not correct. And I believe DMA_GLOBAL_POOL should not be
selected by ARCH_SOCFAMILIY, instead, only ARCH under some specific
conditions can select it globaly, for example NOMMU ARM and so on,
because it's designed for special cases such as "nommu cases where
non-cacheable memory lives in a fixed place in the physical address
map" as pointed out by Robin.

Fix the issue by making ARCH_R9A07G043 (riscv version) depend on
NONPORTABLE, thus generic defconfig won't select ARCH_R9A07G043 by
default. And even for random config case, there will be less debug
effort once we see NONPORTABLE is enabled.
Reported-by: Drew Fustini <dfustini@baylibre.com>
Closes: https://lore.kernel.org/linux-riscv/ZRuamJuShOnvP1pr@x1/
Fixes: 484861e0 ("soc: renesas: Kconfig: Select the required configs for RZ/Five SoC")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Drew Fustini <dfustini@baylibre.com>
Link: https://lore.kernel.org/r/20231004150856.2540-1-jszhang@kernel.orgSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>