mmc: renesas_sdhi: Add RZ/V2M compatible string

The SDHI/eMMC IPs found with the RZ/V2M (a.k.a. r9a09g011), are
very similar to the ones found in R-Car Gen3, but they are not
exactly the same, and as a result need an SoC specific compatible
string for fine tuning driver support.

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20221213230129.549968-4-fabrizio.castro.jz@renesas.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>