mmc: renesas_sdhi: Flag non-standard SDnH handling for V3M

V3M handles SDnH differently than other Gen3 SoCs, so let's add a
separate entry for that. This will allow better SDnH handling in the
future.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20211110191610.5664-5-wsa+renesas@sang-engineering.com


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